What is "family of surfaces"

Family \Fam"i*ly\, n.; pl. Families. [L. familia, fr. famulus servant; akin to Oscan famel servant, cf. faamat he dwells, Skr. dh[=a]man house, fr. dh[=a]to set, make, do: cf. F. famille. Cf. Do, v. t., Doom, Fact, Feat.]

1. The collective body of persons who live in one house, and under one head or manager; a household, including parents, children, and servants, and, as the case may be, lodgers or boarders.

2. The group comprising a husband and wife and their dependent children, constituting a fundamental unit in the organization of society.

   The welfare of the family underlies the welfare of society.
   --H. Spencer.

3. Those who descend from one common progenitor; a tribe, clan, or race; kindred; house; as, the human family; the family of Abraham; the father of a family.

   Go ! and pretend your family is young.
   --Pope.

4. Course of descent; genealogy; line of ancestors; lineage.

5. Honorable descent; noble or respectable stock; as, a man of family.

6. A group of kindred or closely related individuals; as, a family of languages; a family of States; the chlorine family.

7. (Biol.) A group of organisms, either animal or vegetable, related by certain points of resemblance in structure or development, more comprehensive than a genus, because it is usually based on fewer or less pronounced points of likeness. In zo["o]logy a family is less comprehesive than an order; in botany it is often considered the same thing as an order. Family circle. See under Circle. Family man.

   1. A man who has a family; esp., one who has a wife and children living with him and dependent upon him.

   2. A man of domestic habits. ``The Jews are generally, when married, most exemplary family men.''
      --Mayhew.

      Family of curves or Family of surfaces (Geom.), a group of curves or surfaces derived from a single equation.

      In a family way, like one belonging to the family. ``Why don't we ask him and his ladies to come over in a family way, and dine with some other plain country gentlefolks?''
      --Thackeray.

      In the family way, pregnant. [Colloq. euphemism]