Source : Webster's Revised Unabridged Dictionary (1913)

Sauce \Sauce\, n. [F., fr. OF. sausse, LL. salsa, properly, salt
   pickle, fr. L. salsus salted, salt, p. p. of salire to salt,
   fr. sal salt. See {Salt}, and cf. {Saucer}, {Souse} pickle,
   {Souse} to plunge.]
   1. A composition of condiments and appetizing ingredients
      eaten with food as a relish; especially, a dressing for
      meat or fish or for puddings; as, mint sauce; sweet sauce,
      etc. ``Poignant sauce.'' --Chaucer.

            High sauces and rich spices fetched from the Indies.
                                                  --Sir S.
                                                  Baker.

   2. Any garden vegetables eaten with meat. [Prov. Eng. &
      Colloq. U.S.] --Forby. Bartlett.

            Roots, herbs, vine fruits, and salad flowers . . .
            they dish up various ways, and find them very
            delicious sauce to their meats, both roasted and
            boiled, fresh and salt.               --Beverly.

   3. Stewed or preserved fruit eaten with other food as a
      relish; as, apple sauce, cranberry sauce, etc. [U.S.]
      ``Stewed apple sauce.'' --Mrs. Lincoln (Cook Book).

   4. Sauciness; impertinence. [Low.] --Haliwell.

   {To serve one the same sauce}, to retaliate in the same kind.
      [Vulgar]

Sauce \Sauce\ (s[add]s), v. t. [Cf. F. saucer.] [imp. & p. p.
   {Sauced} (s[add]st); p. pr. & vb. n. {Saucing}
   (s[add]"s[i^]ng).]
   1. To accompany with something intended to give a higher
      relish; to supply with appetizing condiments; to season;
      to flavor.

   2. To cause to relish anything, as if with a sauce; to tickle
      or gratify, as the palate; to please; to stimulate; hence,
      to cover, mingle, or dress, as if with sauce; to make an
      application to. [R.]

            Earth, yield me roots; Who seeks for better of thee,
            sauce his palate With thy most operant poison!
                                                  --Shak.

   3. To make poignant; to give zest, flavor or interest to; to
      set off; to vary and render attractive.

            Then fell she to sauce her desires with
            threatenings.                         --Sir P.
                                                  Sidney.

            Thou sayest his meat was sauced with thy
            upbraidings.                          --Shak.

   4. To treat with bitter, pert, or tart language; to be
      impudent or saucy to. [Colloq. or Low]

            I'll sauce her with bitter words.     --Shak.

Sauce \Sauce\ (s[=o]s), n. [F.] (Fine Art)
   A soft crayon for use in stump drawing or in shading with the
   stump.

Source : WordNet®

sauce
     n : flavorful relish or dressing or topping served as an
         accompaniment to food

sauce
     v 1: behave saucy or impudently towards
     2: dress (food) with a relish
     3: add zest or flavor to, make more interesting; "sauce the
        roast"