- anything built or serving to bar passage, as a railing, fence, or the like: People may pass through the barrier only when their train is announced.
- any natural bar or obstacle: a mountain barrier.
- anything that restrains or obstructs progress, access, etc.: a trade barrier.
- a limit or boundary of any kind: the barriers of caste.
- an Antarctic ice shelf or ice front.
- barrier beach.
- the palisade or railing surrounding the ground where tourneys and jousts were carried on.
- a fortress or stockade.
- anything serving to obstruct passage or to maintain separation, such as a fence or gate
- anything that prevents or obstructs passage, access, or progress
- anything that separates or hinders union
- an exposed offshore sand bar separated from the shore by a lagoon
- (as modifier)
- that part of the Antarctic icecap extending over the sea
