from The American Heritage® Dictionary of the English Language, 4th Edition

n. A fundamental social group in society typically consisting of one or two parents and their children.

n. Two or more people who share goals and values, have long-term commitments to one another, and reside usually in the same dwelling place.

n. All the members of a household under one roof.

n. A group of persons sharing common ancestry. See Usage Note at collective noun.

n. Lineage, especially distinguished lineage.

n. A locally independent organized crime unit, as of the Cosa Nostra.

n. A group of like things; a class.

n. A group of individuals derived from a common stock: the family of human beings.

n. Biology A taxonomic category of related organisms ranking below an order and above a genus. A family usually consists of several genera. See Table at taxonomy.

n. Linguistics A group of languages descended from the same parent language, such as the Indo-European language family.

n. Mathematics A set of functions or surfaces that can be generated by varying the parameters of a general equation.

n. Chemistry A group of elements with similar chemical properties.

n. Chemistry A vertical column in the periodic table of elements.

adj. Of or having to do with a family: family problems.

adj. Being suitable for a family: family movies.

Definition via Wordnik
Site by Automattic Design