Source : Webster's Revised Unabridged Dictionary (1913)

Brier \Bri"er\, Briar \Bri"ar\, n. [OE. brere, brer, AS.
   br[=e]r, br[ae]r; cf. Ir. briar prickle, thorn, brier, pin,
   Gael. preas bush, brier, W. prys, prysg.]
   1. A plant with a slender woody stem bearing stout prickles;
      especially, species of {Rosa}, {Rubus}, and {Smilax}.

   2. Fig.: Anything sharp or unpleasant to the feelings.

            The thorns and briers of reproof.     --Cowper.

   {Brier root}, the root of the southern {Smilax laurifolia}
      and {S. Walteri}; -- used for tobacco pipes.

   {Cat brier}, {Green brier}, several species of Smilax ({S.
      rotundifolia}, etc.)

   {Sweet brier} ({Rosa rubiginosa}). See {Sweetbrier}.

   {Yellow brier}, the {Rosa Eglantina}.