family of curves

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.
      [1913 Webster]

   2. The group comprising a husband and wife and their
      dependent children, constituting a fundamental unit in the
      organization of society.
      [1913 Webster]

            The welfare of the family underlies the welfare of
            society.                              --H. Spencer.
      [1913 Webster]

   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.
      [1913 Webster]

            Go ! and pretend your family is young. --Pope.
      [1913 Webster]

   4. Course of descent; genealogy; line of ancestors; lineage.
      [1913 Webster]

   5. Honorable descent; noble or respectable stock; as, a man
      of family.
      [1913 Webster]

   6. A group of kindred or closely related individuals; as, a
      family of languages; a family of States; the chlorine
      family.
      [1913 Webster]

   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 Zoology a family is less comprehesive than an
      order; in botany it is often considered the same thing as
      an order.
      [1913 Webster]

   {Family circle}. See under {Circle}.

   {Family man}.
      (a) A man who has a family; esp., one who has a wife and
          children living with him and dependent upon him.
      (b) 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]
      [1913 Webster]