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.]