Source : Webster's Revised Unabridged Dictionary (1913)

Barb \Barb\, n. [F. barbe, fr. L. barba beard. See {Beard}, n.]
   1. Beard, or that which resembles it, or grows in the place
      of it.

            The barbel, so called by reason of his barbs, or
            wattles in his mouth.                 --Walton.

   2. A muffler, worn by nuns and mourners. [Obs.]

   3. pl. Paps, or little projections, of the mucous membrane,
      which mark the opening of the submaxillary glands under
      the tongue in horses and cattle. The name is mostly
      applied when the barbs are inflamed and swollen. [Written
      also {barbel} and {barble}.]

   4. The point that stands backward in an arrow, fishhook,
      etc., to prevent it from being easily extracted. Hence:
      Anything which stands out with a sharp point obliquely or
      crosswise to something else. ``Having two barbs or
      points.'' --Ascham.

   5. A bit for a horse. [Obs.] --Spenser.

   6. (Zo["o]l.) One of the side branches of a feather, which
      collectively constitute the vane. See {Feather}.

   7. (Zo["o]l.) A southern name for the kingfishes of the
      eastern and southeastern coasts of the United States; --
      also improperly called {whiting}.

   8. (Bot.) A hair or bristle ending in a double hook.

Barb \Barb\, v. t. [imp. & p. p. {Barbed} (?); p. pr. & vb. n.
   {Barbing}.]
   1. To shave or dress the beard of. [Obs.]

   2. To clip; to mow. [Obs.] --Marston.

   3. To furnish with barbs, or with that which will hold or
      hurt like barbs, as an arrow, fishhook, spear, etc.

            But rattling storm of arrows barbed with fire.
                                                  --Milton.

Barb \Barb\, n. [F. barbe, fr. Barbarie.]
   1. The Barbary horse, a superior breed introduced from
      Barbary into Spain by the Moors.

   2. (Zo["o]l.) A blackish or dun variety of the pigeon,
      originally brought from Barbary.

Barb \Barb\, n. [Corrupted fr. bard.]
   Armor for a horse. Same as 2d {Bard}, n., 1.

Source : WordNet®

barb
     n 1: an aggressive remark directed at a person like a missile and
          intended to have a telling effect; "his parting shot was
          `drop dead'"; "she threw shafts of sarcasm"; "she takes
          a dig at me every chance she gets" [syn: {shot}, {shaft},
           {slam}, {dig}, {jibe}, {gibe}]
     2: the pointed part of barbed wire
     3: a subsidiary point facing opposite from the main point that
        makes an arrowhead or spear hard to remove
     4: one of the parallel filaments projecting from the main shaft
        of a feather

barb
     v 1: provide with barbs; "barbed wire"
     2: provide with barbs; "barbed wire"