to keep someone in (or out), using a blockade, especially ships in a port
to close or block a road etc., using a barricade
A barrier constructed across a road, especially as a military defence
An obstacle, barrier, or bulwark.
A place of confrontation.
To inadvertently prevent (a person, particularly oneself) from entering a place, by leaving it locked.
To prevent from accessing a data structure.
An event in which an employer bars employees from working as a tactic in negotiating terms of employment, particularly in response to a strike or threat to strike.