Definition of: barrier

(bar′ē·ər) noun
1. Any line of boundary and separation, natural or artificial, placed or serving as a limitation or obstruction.
2. Something that bars, keeps out, obstructs progress, or prevents encroachment: a barrier to ambition; a language barrier.
3. A palisade or stockade to defend the entrance to a fortified place.
4. A fortress on a frontier commanding a main passage into a country; a customs gate.
5. A fence or railing to shut out trespassers or strangers.
6. The narrow blank space which separates the frames of a motion-picture film or divides the sound track from the picture track.
7. plural The palisades enclosing the ground for a tournament; the lists.
8. Geog. Sometimes cap. The part of the ice cap of Antarctica extending over the ocean beyond the land. [<OF barriere <barre bar] Synonyms: bar, barricade, breastwork, bulwark, hindrance, obstacle, obstruction, parapet, prohibition, rampart, restraint, restriction. A bar is something that is or may be firmly fixed, ordinarily with intent to prevent entrance or egress; as, the bars of a prison cell. A barrier obstructs, but is not necessarily impassable. Barricade denotes some hastily piled obstruction, commonly an improvised street fortification. A parapet is a low or breast-high wall, as about the edge of a roof; in military use, such a wall for the protection of troops; a rampart is the embankment surrounding a fort, on which the parapet is raised; the word rampart is often used as including the parapet. Bulwark is a general word for any defensive wall, but in present technical use it signifies the raised side of a ship above the upper deck, topped by the rail. Compare BOUNDARY, IMPEDIMENT, RAMPART. Antonyms: admittance, entrance, opening, passage, road, thoroughfare, transit.