Civilization describes a complex way of life that came about as people began to develop networks of urban settlements.
    The earliest civilizations developed between 4000 and 3000 BCE, when the rise of agriculture and trade allowed people to have surplus food and economic stability. Many people no longer had to practice farming, allowing a diverse array of professions and interests to flourish in a relatively confined area.
    Civilizations first appeared in Mesopotamia (what is now Iraq) and later in Egypt. Civilizations thrived in the Indus Valley by about 2500 BCE, in China by about 1500 BCE and in Central America (what is now Mexico) by about 1200 BCE. Civilizations ultimately developed on every continent except Antarctica.
    Characteristics of Civilization
    All civilizations have certain characteristics. These include: (1) large population centers; (2) monumental architecture and unique art styles; (3) shared communication strategies; (4) systems for administering territories; (5) a complex division of labor; and (6) the division of people into social and economic classes.
    Urban Areas
    Large population centers, or urban areas (1), allow civilizations to develop, although people who live outside these urban centers are still part of that region’s civilization. Rural residents of civilizations may include farmers, fishers, and traders, who regularly sell their goods and services to urban residents.
    The huge urban center of Teotihuacan, in modern-day Mexico, for example, had as many as 200,000 residents between 300 and 600 CE. The development of the Teotihuacano civilization was made possible in part by the rich agricultural land surrounding the city. As land was cultivated, fewer farmers could supply more food staples, such as corn and beans, to more people.
    Trade also played a part in Teotihuacan’s urban development. Much of the wealth and power of Teotihuacan was due to excavating and trading the rich deposits of obsidian around the city. Obsidian is a hard volcanic rock that was highly valued as a cutting tool. Teotihuacano merchants traded (exported) obsidian to surrounding cultures in exchange for goods and services imported to Teotihuacano settlements.
    All civilizations work to preserve their legacy by building large monuments and structures (2). This is as true today as it was thousands of years ago. 
    For example, the ancient monuments at Great Zimbabwe are still consistently used as a symbol of political power in the modern nation of Zimbabwe. Great Zimbabwe, constructed between 1100 and 1450, describes the ruins of the capital of the Kingdom of Zimbabwe. At its peak, Great Zimbabwe was inhabited by more than 10,000 people and was part of a trading network that extended from the Maghreb, through the eastern coast of Africa, and as far east as India and China.
    Great Zimbabwe is a testament to the sophistication and ingenuity of ancestors of the local Shona people. Politicians like Robert Mugabe, the president who led Zimbabwe for nearly 40 years in the 20th and 21st centuries, built their entire political identities by associating themselves with the ancient civilization’s monumental architecture
    Buildings are not the only monuments that define civilizations. The distinct artistic style of Great Zimbabwe included representations of native animals carved in soapstone. The stylized stone sculptures known as “Zimbabwe Birds”, for example, remain an emblem of Zimbabwe, appearing on the nation’s flag, currency, and coats of arms.
    Shared Communication
    Shared communication (3) is another element that all civilizations share. Shared communication may include spoken language; alphabets; numeric systems; signs, ideas, and symbols; and illustration and representation.
    Shared communication allows the infrastructure necessary for technology, trade, cultural exchange, and government to be developed and shared throughout the civilization. The Inca civilization, for example, had no written script that we know of, but its complex khipu system of accounting allowed the government to conduct censuses of its population and production across the vast stretch of the Andes mountains. A khipu is a recording device made of a series of strings knotted in particular patterns and colors.
    Written language in particular allows civilizations to record their own history and everyday events—crucial for understanding ancient cultures. The world's oldest known written language is Sumerian, which developed in Mesopotamia around 3100 BCE. The most familiar form of early Sumerian writing was called cuneiform, and was made up of different collections of wedge (triangle) shapes. The earliest Sumerian writing was record-keeping. Just like written records of modern civilizations, Sumerian cuneiform kept track of taxes, grocery bills, and laws for things like theft.
    Written language was a key part of shared communication during the Islamic Golden Age, which flourished in southern Europe, northern Africa, and western Asia from the seventh to the 13th centuries. So-called “Arabic numerals” and the Arabic language were shared communications that allowed diverse cultures across the Arabic world to contribute the dazzling advances in mathematics, science, technology, and the arts.
    Infrastructure and Administration
    All civilizations rely on government administration—bureaucracy. (4) Perhaps no civilization better exemplifies this than ancient Rome.
    The word “civilization” itself comes from the Latin word civis, meaning "citizen." Latin was the language of ancient Rome, whose territory stretched from the Mediterranean basin all the way to parts of Great Britain in the north and the Black Sea to the east. To rule an area that large, the Romans, based in what is now central Italy, needed an effective system of government administration and infrastructure.
    Romans used a variety of methods to administer their republic and, later, empire. Engineering, for instance, was a key part of Roman administration. Romans built a network of roads so that communication between far-away territories was as efficient as possible. Roads also made travel by the Roman military much easier. Romans built structures of their civilization everywhere they went: aqueducts supplied freshwater to towns for improved sanitation and hygiene, for example. 
    Language also played a part in Roman infrastructure. Romans spread the Latin language throughout southern Europe. The so-called "Romance languages" (Spanish, French, Portuguese, Romanian, Catalan, and Italian) are called that because they all developed from the Roman language: Latin. Having a similar language made communication and leadership easier for Rome in its far-flung territories.
    Roman leaders relied on a series of legal codes for administration. These codes helped structure laws between different parts of Roman territory, as well as between rich and poor, men and women, slave and free. Roman laws included restrictions on marriage, ownership of land, and access to professions such as priesthoods. 
    One of Rome’s most lasting contributions to Western Civilization was the establishment of legal culture itself. Roman law was largely public, and jurists created such formalities as legal language and procedure that would define European law for centuries. In fact, “Roman law” describes the legal system used throughout Western Europe through the 18th century.
    Finally, Romans used local leaders, as well as Romans, to administer the law in their territories. Residents were more familiar with their own leaders, and more likely to follow their announcements. Israeli leaders worked with Roman authorities in the Roman territory of Palestine, for example, while British leaders often worked with Romans on the island of Great Britain. Some people born in Roman territories eventually became Roman emperors: The emperor Constantine, for instance, was born in what is now Serbia; the emperor Hadrian may have been born in what is now Spain. This interaction reduced conflict between Rome and its territories.
    Division of Labor
    Civilizations are marked by complex divisions of labor (5). This means that different people perform specialized tasks. In a purely agricultural society, members of the community are largely self-sufficient, and can provide food, shelter, and clothing for themselves. In a complex civilization, farmers may cultivate one type of crop and depend on other people for other foods, clothing, shelter, and information.
    Civilizations that depend on trade are specially marked by divisions of labor. The city of Timbuktu, in what is now Mali, was an important trading center for several African civilizations. Residents of Timbuktu specialized in trading such goods as gold, ivory, or slaves. Other residents provided food or shelter for trade caravans traveling on camels from the Sahara Desert. The urban center of Timbuktu was also a center of learning. Its division of labor included not only merchants, but doctors, religious leaders, and artists.
    Class Structure
    The last element that is key to the development of civilizations is the division of people into classes (6). This is a complex idea that can be broken down into two parts: income and type of work performed. Changing classes has traditionally been difficult and happens over generations.
    Classes can mean groups of people divided by their income. This division is sometimes characterized as “economic class.” Modern Western Civilization often divides economic classes into wealthy, middle-class, and poor. In medieval civilizations of Europe, there were fewer economic classes. Kings and queens had enormous amounts of money and land. Serfs, or people who worked the land, had almost nothing. Eventually, a merchant economic class developed.
    Class can also refer to the type of work people perform. There are many divisions of social class. Social class is often associated with economic class, but not strictly defined by it.
    In the ancient civilization of China, there were four major types of social classes. Scholars and political leaders (known as shi) were the most powerful social class. Farmers and agricultural workers (nong) were the next most-powerful group. Artists (gong), who made everything from horseshoes to silk robes, were the next order of social class. At the bottom of the social classes were the merchants and traders, who bought and sold goods and services. Known as shang, these merchants were often much wealthier than the other classes but had a lower social status.
    Development of Civilization
    Civilizations expand through trade, conflict, and exploration. Usually, all three elements must be present for a civilization to grow and remain stable for a long period of time. 
    The physical and human geography of Southeast Asia allowed these attributes to develop in the Khmer civilization, for example. The Khmer flourished in parts of what are now Cambodia, Thailand, Laos, Vietnam, and Myanmar between 800 and 1400.
    The Khmer maintained vibrant trading relationships throughout East Asia, the Indian subcontinent, and even Europe and Africa through the Silk Road, a collection of both overland and maritime trade routes. 
    The Silk Road linked the spice and silk markets of Asia with the merchants of Europe. Southeast Asia’s extensive network of waterways facilitated trade, with the Khmer capital of Angkor being built on the shores of Southeast Asia’s largest freshwater lake, Tonle Sap. The outflowing Tonle Sap River is a tributary of the mighty Mekong River, which connects Southeast Asia with the Tibetan Plateau in the north and the South China Sea in the south.
    In addition to material goods, the Khmer civilization facilitated a powerful trade in ideas. In particular, the Khmer were instrumental in spreading the influence of Buddhist and Hindu cultures from the Indian subcontinent to Southeast and East Asia.
    The primary conflicts of the Khmer civilization were waged with neighboring communities—the Cham, the Vietnamese, and the Thai. The Cham were a collection of kingdoms in what is today central and southern Vietnam, while the ancient Vietnamese influence extended through what is today northern Vietnam. Thai kingdoms such as Sukothai and Ayutthaya flourished in what are now Thailand, Cambodia, and Malaysia.
    The Khmer civilization was founded on the consistent resistance of political pressure from the Cham and Vietnamese, but it ultimately could not withstand pressure from Thai civilizations. Thousands of Thai peoples migrated from the north (what is now the Yunnan region of China), establishing small kingdoms in the southwest of the Khmer Empire. Eventually, these kingdoms became strong enough to annex Khmer territory, leading to Ayutthaya’s conquest of the Khmer capital of Angkor in 1431.
    Exploration and Innovation
    The Khmer civilization relied heavily on rice farming, and developed a complex irrigation system to take advantage of the rivers and wetlands that dotted their territory. An efficient series of irrigation canals and reservoirs, called barays, allowed fewer farmers to produce more rice. This, in turn, allowed more people to pursue non-agricultural lifestyles and migrate to great urban areas, such as Angkor. 
    Angkor, the capital of the ancient Khmer civilization, is home to one of the largest most distinctive religious monuments in the world, Angkor Wat. Angkor Wat was originally constructed as a series of shrines to the Hindu god Vishnu in the early 12th century, although it became a Buddhist temple complex less than a hundred years later. 
    Angkor Wat and its sister complex, Angkor Thom, are beautiful examples of classic Khmer architecture. The towering, stepped pyramid towers of Angkor Wat are called “temple mountains.” The towers are surrounded by open gallery walkways, and the entire structure is enclosed by a wall and square moat. The thousands of square meters of wall space at Angkor Wat and Angkor Thom are decorated by thousands of bas-reliefs and sculptures depicting Hindu stories and characters.
    The Khmer monument at Angkor Wat helps define the modern nation of Cambodia today. It is the nation’s primary tourist attraction, a World Heritage Site, and even appears on the Cambodian flag.
    Fall of Civilizations
    Many civilizations have flourished and then failed or fallen apart. There are many reasons for this, but many historians point to three patterns in the fall of civilizations: internal change, external pressure, and environmental collapse. The fall of civilizations is never the result of a single event or pattern.
    Sometimes, civilizations seem to “disappear” entirely.
    Internal Change
    Population dynamics are the most pervasive forces of internal change to a civilization. A sudden population shift or a shift in demographics may force a civilization’s infrastructure to break down. 
    Populations may grow, due to migration or a period of unusual health. Populations may shrink, due to disease, extreme weather, or other environmental factors. 
    Finally, populations may redefine themselves. As civilizations grow, cities may grow larger and become more culturally distinct from rural, agricultural areas. Large empires may extend across such large regions that languages, cultures, and customs may dilute the identity of the empire’s residents.
    Internal changes contributed to the collapse of the Maya civilization, which had thrived in Mesoamerica for more than a thousand years. The “Classic Maya” collapse happened relatively quickly in the 800s. Diseases such as dysentery and lethal hemorrhagic fevers killed and disabled thousands of Mayans. Millions more were forced to relocate from cities to more rural areas. Such huge population shifts reduced the ability of the Maya to communicate, administrate, and unite against outside forces and natural disasters (such as drought).
    External Pressure
    The clearest example of external pressure on a civilization is foreign invasion or sustained warfare. Protecting a civilization’s borders can be extremely expensive and demand a strong military at the expense of developing or maintaining other aspects of a civilization.
    External pressure can lead to the relatively abrupt end of a civilization (and, often, the adoption of another). The fall of the Aztec Empire with the arrival of European conquistadores is such an example.
    External pressures can also lead to the gradual diminishing of a civilization. The “fall” of what we often think of as Ancient Egypt is a good example of how external pressures can redefine a civilization over hundreds of years. Egypt had faced longstanding, intermittent conflict on its borders, with competing civilizations such as the Nubians (to the south), the Assyrians (in the Middle East), and the Libyans (to the west). Later, Egypt encountered the civilizations of Ancient Greece and Rome, and eventually became part of the Roman Empire.
    Ancient Egypt also faced external pressures not directly associated with armed conflict. The powerful forces of Christianity and Islam influenced the eradication of both hieroglyphics, the writing system of Ancient Egypt, and its polytheistic religion.
    Environmental Collapse
    Some anthropologists think that both natural disasters and misuse of the environment contributed to the decline of many civilizations. 
    Natural hazards such as drought, floods, and tsunamis, become natural disasters as they impact civilizations. 
    Drought contributed to the fall of civilizations such as the Maya and the Indus Valley or Harappan civilization. The Indus Valley Civilization was a Bronze Age civilization in what is now Pakistan, India, and Afghanistan. The Indus Valley Civilization depended on seasonal monsoon rains to supply water for drinking, hygiene, and irrigation. Climate change made monsoons much more unpredictable and seasonal flooding less reliable. Harappans suffered from water-borne diseases and were unable to effectively irrigate their crops. 
    The collapse of Minoan civilization, a major influence on Ancient Greece, is often associated with a catastrophic eruption of the Thera volcano on the island of what is now Santorini. The eruption caused a massive tsunami that reduced the population, trading capabilities, and influence of the Minoans.
    Human activity can also strain the environment to the point of a civilization’s collapse. One of several factors contributing to the collapse of the Viking outpost in Greenland, for instance, was the failure of European settlers to adapt to Greenland’s climate and soil. Farming methods that were successful in the rich, loamy soils of Northern Europe were ill-suited to Greenland’s colder, thinner soil and shorter growing seasons. The land could not support the crops necessary to sustain Viking livestock, including goats, cattle, and sheep. In addition, the land itself was harvested for peat, the outpost’s primary construction material. The Vikings in Greenland also faced internal pressures, such as a weak trading system with Europe, and external pressures, such as a hostile relationship with their Inuit neighbors.
    ‘Lost Civilizations’
    History and myth are rich with “lost civilizations,” entire ways of life that seemed to flourish and then disappear from the historical record.
    The disappearance of the Ancestral Puebloan civilization is one such mystery. Ancestral Puebloan civilization thrived in what is now the Four Corners region of Utah, Colorado, New Mexico, and Arizona. Ancestral Puebloan civilization developed around 1200 BCE and thrived for more than a thousand years.
    Ancestral Puebloan civilization was marked by monumental architecture in the form of apartment-like cliff dwellings and large urban areas known as pueblos. Culturally diverse Ancestral Puebloans were connected by a complex road system, a standard style of religious worship, and a unique art style evidenced by pottery and petroglyphs.
    Ancestral Puebloans seem to have abandoned their urban areas around 1300 CE. The disappearance of this civilization remains a mystery, although most scientists say Ancestral Puebloans engaged in warfare with their Navajo neighbors, internal groups competed for land and resources, and sustained droughts reduced Ancestral Puebloan ability to irrigate crops in the arid Southwest.
    The Pueblo people never disappeared, of course: Diverse groups developed their own, competing civilizations after the Ancestral Puebloans migrated or fell apart. These groups include the Zuni and Hopi civilizations.
    Key Components of Civilization
    Civilization depends on agriculture.

    World Powers
    The so-called "Group of 7" (G7) is an organization of the seven wealthiest democracies in the world. Seven of the eight countries are part of Western civilization: the United States, Canada, the United Kingdom, France, Germany, and Italy. The only G7 member from outside Western civilization is Japan. Japan is usually considered its own civilization.

    Representatives from the G7 usually meet once a year, and discuss international issues, including the spread of disease, economic development, terrorism, and climate change.

    Cradle of Civilization
    The southern part of the modern country of Iraq is called the "Cradle of Civilization." The worlds first cities, writing systems, and large-scale government developed there.

  • Term Part of Speech Definition Encyclopedic Entry
    abandon Verb

    to desert or leave entirely.

    abrupt Adjective

    sudden or quickly changing.

    administer Verb

    to oversee, manage, or be in charge of.

    administration Noun

    responsibilities and policies of the executive branch of the United States government, led by a president, his or her cabinet, and his or her advisers.

    agriculture Noun

    the art and science of cultivating the land for growing crops (farming) or raising livestock (ranching).

    Encyclopedic Entry: agriculture
    alphabet Noun

    system of writing in which each symbol ideally represents one sound unit in the spoken language.

    ancestor Noun

    organism from whom one is descended.

    ancient Adjective

    very old.

    ancient Rome Noun

    civilization founded on the Mediterranean Sea, lasting from the 8th century BCE to about 476 CE.

    annex Verb

    to add or incorporate land into an existing parcel, state, or nation.

    anthropologist Noun

    person who studies cultures and characteristics of communities and civilizations.

    aqueduct Noun

    a pipe or passage used for carrying water from a distance.

    Arabic numeral Noun

    numeric symbols 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, introduced to Western Europe by Arabic scholars in the 12th century.

    architecture Noun

    style and design of buildings or open spaces.

    arid Adjective


    array Noun

    large group.

    aspect Noun

    view or interpretation.

    baray Noun

    rectangular reservoir or artificial lake that is a key feature in Khmer architecture.

    bas-relief Noun

    carving or sculpture in which figures project slightly from a flat background.

    bill Noun

    statement of money owed for goods or services.

    border Noun

    natural or artificial line separating two pieces of land.

    Encyclopedic Entry: border
    Bronze Age Noun

    time period between the Stone Age and the Iron Age. The Bronze Age lasted between 3000 BCE and 500 BCE.

    Buddhist Noun

    person who follows the teachings of Siddhartha Gautama (Buddha).

    canal Noun

    artificial waterway.

    capital Noun

    city where a region's government is located.

    Encyclopedic Entry: capital
    caravan Noun

    group of people who travel together for safety and companionship through difficult territory.

    catastrophic Adjective

    very bad.

    census Noun

    program of a nation, state, or other region that counts the population and usually gives its characteristics, such as age and gender.

    Encyclopedic Entry: census
    characteristic Noun

    physical, cultural, or psychological feature of an organism, place, or object.

    Christianity Noun

    religion based on the teachings of Jesus of Nazareth.

    civilization Noun

    complex way of life that developed as humans began to develop urban settlements.

    Encyclopedic Entry: Key Components of Civilization
    class Noun

    division in society based on income and type of employment.

    climate Noun

    all weather conditions for a given location over a period of time.

    Encyclopedic Entry: climate
    climate change Noun

    gradual changes in all the interconnected weather elements on our planet.

    Encyclopedic Entry: Earth's Changing Climate
    coal Noun

    dark, solid fossil fuel mined from the earth.

    coat of arms Noun

    design consisting of a shield, supporters, crest, and motto, representing an individual, family, state, or organization.

    collapse Verb

    to fall apart completely.

    communication Noun

    sharing of information and ideas.

    compete Verb

    to work against someone or something else for an award or acknowledgment.

    complex Adjective


    conflict Noun

    a disagreement or fight, usually over ideas or procedures.

    conquistador Noun

    Spanish explorer or conqueror of Latin America in the 16th century.

    consistent Adjective

    maintaining a steady, reliable quality.

    continent Noun

    one of the seven main land masses on Earth.

    Encyclopedic Entry: continent
    crop Noun

    agricultural produce.

    Encyclopedic Entry: crop
    cultivate Verb

    to prepare and nurture the land for crops.

    cultural exchange Noun

    sharing and communication between cultures, resulting in the adoption of new or borrowed behaviors.

    culture Noun

    learned behavior of people, including their languages, belief systems, social structures, institutions, and material goods.

    cuneiform Noun

    written language developed by Sumerians and common throughout ancient Mesopotamia, made up of different collections of wedge or triangle shapes.

    currency Noun

    money or other resource that can be used to buy goods and services.

    demographic Adjective

    having to do with the social characteristics and statistics of a population.

    dilute Verb

    to weaken or reduce.

    diminish Verb

    to become smaller or less important.

    disease Noun

    harmful condition of a body part or organ.

    distinct Adjective

    unique or identifiable.

    drought Noun

    period of greatly reduced precipitation.

    Encyclopedic Entry: drought
    dysentery Noun

    possibly fatal disease with severe, bloody diarrhea.

    economic Adjective

    having to do with money.

    efficient Adjective

    performing a task with skill and minimal waste.

    emperor Noun

    ruler of an empire.

    empire Noun

    group of nations, territories or other groups of people controlled by a single, more powerful authority.

    engineering Noun

    the art and science of building, maintaining, moving, and demolishing structures.

    enormous Adjective

    very large.

    eradication Noun

    total destruction.

    evidence Noun

    data that can be measured, observed, examined, and analyzed to support a conclusion.

    expand Verb

    to grow or get larger.

    exploration Noun

    study and investigation of unknown places, concepts, or issues.

    extreme weather Noun

    rare and severe events in the Earth's atmosphere, such as heat waves or powerful cyclones.

    facilitate Verb

    to help or make easier.

    far-flung Adjective

    spread over a great distance.

    farming Noun

    the art, science, and business of cultivating the land for growing crops.

    flood Verb

    to overflow or cover in water or another liquid.

    flourish Verb

    to thrive or be successful.

    food staple Noun

    food that can be prepared, stored, and eaten throughout the year.

    Four Corners Noun

    region at the intersection of four states in the U.S. Southwest: Utah, Colorado, New Mexico, and Arizona.

    generation Noun

    time between an organism's birth and the time it reproduces.

    government Noun

    system or order of a nation, state, or other political unit.

    Great Britain Noun

    large island in Western Europe consisting of the countries of England, Scotland, and Wales.

    grocery Noun

    food or other goods sold at a general store.

    Group of 8 (G8) Noun

    eight wealthiest nations in the world: the United States, Japan, Germany, France, the United Kingdom, Italy, Russia, and Canada. The European Union is also included in the G8.

    growing season Noun

    period in the year when crops and other plants grow rapidly.

    hemorrhagic fever Noun

    sometimes-lethal viral infection (including dengue, Ebola, and yellow fevers) characterized by fever, chills, and malaise followed by bleeding. 

    hieroglyphics Plural Noun

    written language using images to represent words.

    Hindu Noun

    religion of the Indian subcontinent with many different sub-types, most based around the idea of "daily morality."

    hostile Adjective

    confrontational or unfriendly.

    human geography Noun

    the study of the way human communities and systems interact with their environment.

    hygiene Noun

    science and methods of keeping clean and healthy.

    income Noun

    wages, salary, or amount of money earned.

    income Noun

    wages, salary, or amount of money earned.

    Indian subcontinent Noun

    landmass in south-central Asia carried by the Indian tectonic plate, including the peninsula of India.

    infrastructure Noun

    structures and facilities necessary for the functioning of a society, such as roads.

    ingenuity Noun

    cleverness or resourcefulness.

    instrumental Adjective


    intermittent Adjective

    starting and stopping, not consistent.

    invasion Noun

    an attack or move to take possession.

    irrigation Noun

    watering land, usually for agriculture, by artificial means.

    Encyclopedic Entry: irrigation
    Islam Noun

    religion based on the words and philosophy of the prophet Mohammed.

    Islamic Golden Age Noun

    (600-1200) time period when science and art flourished in north Africa and the Middle East, where the Islamic religion is widely practiced.

    ivory Noun

    hard, white substance that forms the teeth or tusks of some animals.

    jury Noun

    group of people selected to determine facts in a specific case.

    Encyclopedic Entry: jury
    khipu Noun

    knotted cord used by the ancient Incan Empire to record events, census data, and accounts. Also spelled quipu.

    kingdom Noun

    type of government with a king or queen as its leader, or the land ruled by that king or queen.

    Encyclopedic Entry: kingdom
    labor Noun

    work or employment.

    Latin Noun

    language of ancient Rome and the Roman Empire.

    legacy Noun

    material, ideas, or history passed down or communicated by a person or community from the past.

    lethal Adjective


    livestock noun, plural noun

    animals raised for sale and profit.

    loam Noun

    fertile soil rich in sand, silt, and smaller amounts of clay.

    Maghreb Noun

    region in North Africa made of five countries: Morocco, Algeria, Tunisia, Libya, and Mauritania.

    maritime Adjective

    having to do with the ocean.

    medieval Adjective

    having to do with the Middle Ages (500-1400) in Europe.

    Mediterranean basin Noun

    land that surrounds the Mediterranean Sea.

    merchant Noun

    person who sells goods and services.

    Mesopotamia Noun

    ancient region between the Tigris and Euphrates Rivers, today lying mostly in Iraq.

    middle class Noun

    people and culture characterized by incomes between the working class and the wealthy.

    migrate Verb

    to move from one place or activity to another.

    migrate Verb

    to move from one place or activity to another.

    migration Noun

    movement of a group of people or animals from one place to another.

    military Noun

    armed forces.

    misuse Noun

    incorrect or ignorant use of resources.

    moat Noun

    trench around a castle, filled with water, to prevent or delay attack or invasion.

    monsoon Noun

    seasonal change in the direction of the prevailing winds of a region. Monsoon usually refers to the winds of the Indian Ocean and South Asia, which often bring heavy rains.

    Encyclopedic Entry: monsoon
    monument Noun

    large structure representing an event, idea, or person.

    monumental Adjective

    very large, serious, and important.

    myth Noun

    legend or traditional story.

    natural disaster Noun

    an event occurring naturally that has large-scale effects on the environment and people, such as a volcano, earthquake, or hurricane.

    obsidian Noun

    black glass formed as lava cools above ground.

    outpost Noun

    settlement or station located in a remote area.

    peat Noun

    layers of partially decayed organic material found in some wetlands. Peat can be dried and burned as fuel.

    petroglyph Noun

    carving or drawing on rock.

    polytheistic Adjective

    having a belief in many gods and goddesses.

    poor Noun

    people and culture characterized by very low income.

    population center Noun

    settlement with many residents, often an urban area.

    population dynamics Plural Noun

    branch of life science that studies patterns in the size and age of specific populations.

    public Noun

    people of a community.

    pueblo Noun

    adobe or stone dwelling.

    punk Noun

    style of loud, energetic music.

    pyramid Noun

    three-dimensional shape with a square base and triangular sides that meet in a point.

    Encyclopedic Entry: Pyramid
    represent Verb

    to stand for a person, community, or idea.

    republic Noun

    system of government where power rests in citizens who vote and representatives who stand for those citizens. The United States is a republic.

    reservoir Noun

    natural or man-made lake.

    Encyclopedic Entry: reservoir
    resistance Noun

    the act of opposing something.

    Romance languages Noun

    spoken and written forms of communication that share a root in the Latin language: Spanish, French, Italian, Catalan, Portuguese, and Romanian.

    Roman law Noun

    legal system of ancient Rome, mostly associated with the emperor Justinian, and adapted by most of Europe through the 18th century. 

    rural area Noun

    regions with low population density and large amounts of undeveloped land. Also called "the country."

    Encyclopedic Entry: rural area
    sanitation Noun

    promotion of hygiene, health, and cleanliness.

    scholar Noun

    educated person.

    seasonal flooding Noun

    overflowing of a body of water from its banks, usually predicted by yearly rains or storms.

    serf Noun

    type of slave forced to work on land owned by others in return for protection.

    shrine Noun

    place of worship or spiritual devotion.

    silk Noun

    soft, strong fiber spun by some moth larvae, spiders, and other animals.

    Silk Road Noun

    ancient trade route through Central Asia linking China and the Mediterranean Sea.

    similar Adjective

    alike or resembling.

    soil Noun

    top layer of the Earth's surface where plants can grow.

    sophisticated Adjective

    knowledgeable or complex.

    sophisticated Adjective

    knowledgeable or complex.

    specialize Verb

    to study, work, or take an interest in one area of a larger field of ideas.

    spice Noun

    tasty and aromatic plant substances used in cooking.

    surplus Noun

    more than what is needed or wanted.

    sustain Verb

    to support.

    tax Noun

    money or goods citizens provide to government in return for public services such as military protection.

    technology Noun

    the science of using tools and complex machines to make human life easier or more profitable.

    territory Noun

    land an animal, human, or government protects from intruders.

    testament Noun

    proof or evidence.

    thrive Verb

    to develop and be successful.

    tourist Noun

    person who travels for pleasure.

    trade Noun

    buying, selling, or exchanging of goods and services.

    trade route Noun

    path followed by merchants or explorers to exchange goods and services.

    tributary Noun

    stream that feeds, or flows, into a larger stream.

    Encyclopedic Entry: tributary
    tsunami Noun

    ocean waves triggered by an earthquake, volcano, or other movement of the ocean floor.

    unique Adjective

    one of a kind.

    urban Adjective

    having to do with city life.

    urban area Noun

    developed, densely populated area where most inhabitants have nonagricultural jobs.

    Encyclopedic Entry: urban area
    Viking Noun

    seafaring people and culture native to Scandinavia between the 7th and 12th centuries.

    volcanic Adjective

    having to do with volcanoes.

    volcano Noun

    an opening in the Earth's crust, through which lava, ash, and gases erupt, and also the cone built by eruptions.

    Encyclopedic Entry: Plate Tectonics and Volcanic Activity
    warfare Noun

    armed conflict between two or more groups of people, usually representing different nations or other political organizations.

    water-borne Adjective

    transported or carried by water.

    wealthy Adjective

    very rich.

    wedge Noun

    triangle shape.

    Western Civilization Noun

    civilizations of European origin.

    wetland Noun

    area of land covered by shallow water or saturated by water.

    Encyclopedic Entry: wetland
    World Heritage Site Noun

    location recognized by the United Nations as important to the cultural or natural heritage of humanity.