• A family is a group of people related by the ties of blood, marriage, or adoption. Members of a family most often live in a single residence and perform different duties. Members of a family and their duties vary from culture to culture and at different times in history. Who is considered a family member, and what responsibilities that family member has, may depend on their age, sex, and relationship to other family members.

    A nuclear family includes a father and a mother, or a single parent, and their children. A nuclear family often lives in a residence separate from other relatives. Nuclear families are one of the most familiar and oldest types of families. They are common in developed countries such as the United States. In many countries with traditions of nuclear families, married couples are expected to move out of their parents homes in order to pursue careers and set up their own household.

    A household in which parents, children, grandparents, and other relatives live is known as an extended family. Extended families are important in agricultural societies because they provide a labor force to work a single unit of family land and perform household tasks. An extended family can also provide care for the elderly and young in the household. In India, for example, extended families usually consist of two or more married couples who share finances and a common kitchen. By sharing responsibilities, an extended family is able to support all members of the household both socially and economically.

    Clans are another form of an extended family. A clans members typically claim a common relative. Clans unify people who might otherwise be divided by their different places of residence or distinct age groups. Clan members and their allies often provide one another with economic and social support. Clans, sometimes called tribes, are an important part of cultural and political life in Central Asia. Clans such as the Buguu, the Sarybagysh, and the Adygine continue to dominate the politics of Kyrgyzstan, for example.

    A family may be led by either a man or a woman. A patriarchal family is one run by the father or eldest male of a household. He usually decides the duties of the women and children in the family. Traditionally in Nigeria, the eldest male is the patriarch, or leader, of the extended family. In this role, the patriarch solves family disputes and divides the familys wealth. The patriarch is also the spiritual leader of the family because he is thought to be the closest to the spirits of the familys ancestors.

    A family in which a woman is the head of the household is known as a matriarchal family. The Mosuo people of southwestern China live in matriarchal families. The Mosuo family is made up of matrilineal members, or people who are related to the matriarch, or female family leader. The family would include the grandmother, mother, the mothers sisters and brothers, and the children of the mother and her sisters. Like the patriarchal family in Nigeria, the mother of a Mosuo family is in charge of the households wealth. If there are many sisters in one family, the smartest and most capable sister will be elected the Dabu, or head of household. Unlike most families in the United States, Mosuo couples do not set up a new family and do not share property. Their children are the responsibility of the female partner. The male partner helps raise the children of his sisters.


    The study of a familys origins and history is known as genealogy. Your genealogy includes all the people who are related to you across all of history. Your siblings, parents, grandparents, and even your great-great-great grandparents each represent a different generation in this ancestry.

    A generation is a set of family members who make up one step, or stage, in your family history. Siblings and cousins are usually in the same generation. Parents are usually a generation older than their children.

    Genealogists are scientists who study ancestry and family history. Genealogists often make a list of all of a persons relatives, and then arrange them in a chart that is organized by generation. This chart is known as a family tree. Newer generations are placed at the bottom, or trunk, of the tree. Older generations, or branches, are placed near the top. The chart resembles a tree in shape because the number of family members is often wider at the top than at the bottom.

    A family tree uses a number of symbols to define how people are related. Arrows indicate a birth. A parallel line indicates a sibling. An equal sign indicates marriage.

    The study of ones family origins has become very popular, and a number of services exist that can help someone trace his or her family history. The Genographic Project, for example, uses advanced technologies to analyze historical patterns in DNA from people around the world. DNA is a material in your cells that stores information about your ancestry. The Genographic Project collects individuals DNA and then runs a test to show maternal or paternal ancestry. By tracing each generations history, the Genographic Project has been able to chart human migration over the course of hundreds of thousands of years.

    Changing Families

    The structure of families is constantly changing. For example, during the Industrial Revolution, a period of technological change in the 18th and 19th centuries, more women began working outside the home. Before the Industrial Revolution, working outside the home was considered a responsibility for male members of the family. Caring for children was considered a responsibility for female members of the family.

    A rise in the number of divorces has led to an increase in the number of stepfamilies. Stepfamilies are families in which one or both members of a couple have children from a previous relationship. The number of one-parent families, where one parent or another adult is the sole provider for their family, has also increased.

    A couple or individual parent may also choose to adopt a child. Parents can adopt children who are related to them or are from a different community, or even a different country. The process of adoption is often long and difficult. Families who choose to adopt usually must get permission from government agencies. Same-sex couples, couples with disabilities, and couples from different ethnicities sometimes face prejudice and legal obstacles when looking to adopt.

    Animal Families

    Animals, much like humans, have different ways of creating and organizing their families.

    Penguins create families that are similar to nuclear families. The same male and female penguin couple meets every season to mate and bear offspring. Both penguins take turns incubating the egg and going for food. After birth, the penguin chick is taken care of by its parents until it sheds its fuzzy down feathers. The chick is then able to leave the family in order to search for its own food and mate.

    Elephants, on the other hand, live in matriarchal families. Each family is made up of three to 25 adult females and their offspring. The females remain close throughout their lifetimes and help raise all of the baby elephants, called calves. The family is led by an older female who makes all the decisions. Male elephants leave their families between the ages of 12 and 15 and have no long-term bonds with any other elephants.

    Some animals have family structures that do not resemble human families. All the honeybees in a single hive are usually related, creating a family with hundreds of members. The matriarch, called the queen bee, is usually the mother of all the bees in the hive. She is the only female that can reproduce. She eats food different from the rest of the bees in the hive. The other female bees, called worker bees, create the honeycomb, take care of the bee larvae, gather food, and make honey. Male bees, called drones, mate with queens from different hives to produce offspring.

    Scientific Families

    The term family is also used in the studies of biology, chemistry, and math. These definitions of family demonstrate how different sets of information are related.

    In biology, the term family describes a group of organisms that come from the same ancestors and share common characteristics. Dogs, wolves, and foxes, for example, are members of the same family, canidae. Much like genealogy, taxonomy is the study of these groups of organisms and their common ancestors. The taxonomy of a certain animal or plant is a chart that describes its ancestry, much like a family tree does for people.

    In chemistry, a family is a group of substances that share certain chemical characteristics and have a common name. Sometimes, a family is a group of elements that appears in the same column of the periodic table of elements. The noble gases, for example, are a chemical family that appears in the far right column of the periodic table.

    In math, a family is a set of equations using the same numbers. There are usually only three numbers in a simple fact family. One, two, and three are the numbers in the family for the equations 1 2=3, 2 1=3, 3-1=2, and 3-2=1.

    A Malaysian family watches the sunset.

    Polygamy describes a family structure in which one person is married to multiple people. Polygyny is one man having more than one wife. Polyandry is one woman having more than one husband. Polygamous families are familiar in some parts of the world today.

    Deep Roots
    Roy Blackmore from Taunton, Somerset, United Kingdom, applied to the Guinness Book of World Records in 2008 to claim the title for the world's largest documented family tree. Blackmore spent more than 28 years tracing his family tree and has listed a whopping 9,390 ancestors and relatives! He can trace his ancestry through 45 generationsall the way back to King Alfred the Great in 880.

  • Term Part of Speech Definition Encyclopedic Entry
    adopt Verb

    to formally raise and care for a child of other biological parents.

    Adygine Noun

    people and culture native to southern Kyrgyzstan.

    agriculture Noun

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

    Encyclopedic Entry: agriculture
    ally Noun

    person or group who supports and cooperates with another person or group.

    analyze Verb

    to study in detail.

    ancestor Noun

    organism from whom one is descended.

    ancestry Noun

    family (genealogical) or historical background.

    animal Noun

    organisms that have a well-defined shape and limited growth, can move voluntarily, acquire food and digest it internally, and can respond rapidly to stimuli.

    bear Verb

    to give birth.

    biology Noun

    study of living things.

    blood Adjective

    linked by a common ancestor.

    bond Noun

    social link or connection.

    Buguu Noun

    people and culture native to northern Kyrgyzstan.

    calf Noun

    young elephant.

    Canidae Noun

    family of mammals that includes dogs, wolves, and foxes.

    capable Adjective

    having the ability to do something.

    characteristic Noun

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

    chart Noun

    diagram, often in the form of a graph or table, with information on the relationships between the subjects represented.

    chemical family Noun

    group of substances that share basic chemical characteristics and have a common name.

    chemistry Noun

    study of the atoms and molecules that make up different substances.

    chick Noun

    young bird.

    claim Verb

    to state as the truth.

    clan Noun

    family or large group of people claiming common ancestry.

    concurrent Adjective

    simultaneous, or at the same time.

    consider Verb

    to think about.

    cousin Noun

    relative, usually sharing a grandparent.

    culture Noun

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

    demonstrate Verb

    to show how something is done.

    developed country Noun

    a nation that has high levels of economic activity, health care, and education.

    disability Noun

    physical or psychological handicap.

    dispute Noun

    debate or argument.

    divorce Noun

    legal end to a marriage.

    DNA Noun

    (deoxyribonucleic acid) molecule in every living organism that contains specific genetic information on that organism.

    document Verb

    to keep track of.

    dog Noun

    domestic animal related to the wolf.

    dominate Verb

    to overpower or control.

    down Noun

    soft, fuzzy feathers of young birds.

    drone Noun

    male bee in a hive, which mates with queen bees from different hives to produce offspring.

    duty Noun

    responsibility or job.

    economic Adjective

    having to do with money.

    elderly Adjective


    elephant Noun

    large mammal with a long trunk, native to Africa and Asia.

    equation Noun

    mathematical statement of the equality of two sets of numbers or values.

    ethnicity Noun

    identity in a group sharing genetic characteristics, culture, language, religion, or history.

    extended family Noun

    household in which parents, children, grandparents, and other relatives live.

    fact family Noun

    set of mathematical equations using the same set of numbers.

    family Noun

    group of organisms that come from the same ancestors and share similar characteristics. Family is also a classification in chemistry and math.

    Encyclopedic Entry: family
    family tree Noun

    chart of a person's relatives, organized by generation.

    father Noun

    male parent.

    feather Noun

    one of the light structures that cover the body of birds, often helping them to fly or keep warm.

    finances Noun

    budget, or money available for a specific project or goal.

    fox Noun

    type of mammal related to a dog with a thin muzzle and thick tail.

    genealogy Noun

    study of a family's ancestry, origins, and history.

    generation Noun

    group in a species made up of members that are roughly the same age.

    Genographic Project Noun

    National Geographic project that uses genealogy to trace the migratory history of the human species.

    government agency Noun

    organization serving the government of a country or nation.

    Guinness World Records Noun

    yearly reference list of facts and achievements.

    hive Noun

    structure where bees live.

    honeybee Noun

    insect that, in a hive with other honeybees, produces honey.

    honeycomb Noun

    wax structure built by bees to hold honey and larvae.

    household Noun

    residence where individuals live as a single family unit.

    incubate Verb

    to heat and take care of eggs until they hatch.

    Industrial Revolution Noun

    change in economic and social activities, beginning in the 18th century, brought by the replacement of hand tools with machinery and mass production.

    King Alfred the Great Noun

    (849899) king of western Britain.

    kitchen Noun

    room or area where food is prepared.

    labor force Noun

    workers or people who are physically and legally able to work. Also called the workforce.

    larva Noun

    a new or immature insect or other type of invertebrate.

    legal Adjective

    allowed by law.

    marriage Noun

    situation where two people form a legal, religious, or social bond.

    mate Verb

    to reproduce or breed.

    maternal Adjective

    having to do with a mother.

    math Noun

    (mathematics) study of the relationship and measurements of quantities using numbers and symbols.

    matriarch Noun

    female leader of a family.

    matriarchal family Noun

    group of related individuals led by a mother or other female.

    matrilineal Adjective

    ancestry traced through female relatives.

    migration route Noun

    path followed by immigrants to a new region.

    Mosou Noun

    people and culture native to southwestern China.

    mother Noun

    female parent.

    noble gas Noun

    one of a group of elements appearing at the far right column of the periodic table of elements: helium (He), neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), or radon (Rn). Also called an inert gas.

    nuclear family Noun

    a mother, a father, and their children.

    offspring Noun

    the children of a person or animal.

    parent Noun

    organism that produces another organism.

    paternal Adjective

    having to do with a father.

    patriarch Noun

    male leader of a family.

    patriarchal family Noun

    group of related individuals led by a father or other male.

    penguin Noun

    bird native to the Antarctic.

    periodic table of elements Noun

    chart listing all chemical elements in order of their atomic weights and numbers.

    polyandry Noun

    situation of a woman having more than one husband.

    polygamy Noun

    situation of a person having more than one spouse.

    polygyny Noun

    situation of a male having more than one wife or mate.

    prejudice Noun

    unfair feeling for or against someone or something without basis in reason.

    property Noun

    goods or materials (including land) owned by someone.

    pursue Verb

    to seek or strive to accomplish.

    queen bee Noun

    only female in a beehive that can reproduce, and usually the mother of all other bees in the hive.

    record Noun

    account of a specific observation or event.

    relate Verb

    to interact with or respond to.

    relatedness Noun

    being connected by similarities.

    reproduce Verb

    to create offspring, by sexual or asexual means.

    resemble Verb

    to look like.

    same-sex couple Noun

    romantic relationship where both partners are either male or female.

    Sarybagysh Noun

    people and culture native to northern Kyrgyzstan.

    sex Noun

    male or female: division into which sexually reproducing organisms are divided.

    sibling Noun

    brother or sister.

    society Noun

    large community, linked through similarities or relationships.

    spiritual Adjective

    having to do with religion or faith.

    stepfamily Noun

    families in which one or both members of a couple have children from a previous relationship.

    structure Noun

    system of organization.

    taxonomy Noun

    study of the identification, classification, and naming of organisms.

    tribe Noun

    community made of one or several family groups sharing a common culture.

    wealth Noun

    amount of money or other valuable materials.

    whopping Adjective

    very large amount.

    wolf Noun

    mammal related to the dog.

    worker bee Noun

    female bees in a hive, responsible for gathering food and maintaining the hive.