\Bar"ri*er\, n. [OE. barrere, barere, F. barri[`e]re,
fr. barre bar. See {Bar}, n.]
1. (Fort.) A carpentry obstruction, stockade, or other
   obstacle made in a passage in order to stop an enemy.
2. A fortress or fortified town, on the frontier of a
   country, commanding an avenue of approach.
3. pl. A fence or railing to mark the limits of a place, or
   to keep back a crowd.
         No sooner were the barriers opened, than he paced
         into the lists.                       --Sir W.
                                               Scott.
4. An any obstruction; anything which hinders approach or
   attack. ``Constitutional barriers.'' --Hopkinson.
5. Any limit or boundary; a line of separation.
         'Twixt that [instinct] and reason, what a nice
         barrier !                             --Pope.
{Barrier gate}, a heavy gate to close the opening through a
   barrier.
{Barrier reef}, a form of coral reef which runs in the
   general direction of the shore, and incloses a lagoon
   channel more or less extensive.
{To fight at barriers}, to fight with a barrier between, as a
   martial exercise. [Obs.]