n.1 a fence or other obstacle that bars advance or access.
2 an obstacle or circumstance that keeps people or things apart, or prevents communication (class barriers; a language barrier).
3 anything that prevents progress or success.
4 a gate at a car park, railway station, etc., that controls access.
5 colloq. sound barrier.
Phrases and idioms:
barrier cream a cream used to protect the skin from damage or infection. barrier reef a coral reef separated from the shore by a broad deep channel.
Etymology: ME f. AF barrere, OF barriere