barrier

American  

[bar-ee-er] / ˈbær i ər /

noun

1. 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.

   Synonyms:

   impediment, hindrance, obstruction, wall, palisade

2. any natural bar or obstacle.

   a mountain barrier.

   Synonyms:

   impediment, hindrance, obstruction

3. anything that restrains or obstructs progress, access, etc..

   a trade barrier.

   Synonyms:

   impediment, hindrance, obstruction

4. a limit or boundary of any kind.

   the barriers of caste.

5. Physical Geography. an Antarctic ice shelf or ice front.

6. barrier beach.

7. History/Historical. barriers, the palisade or railing surrounding the ground where tourneys and jousts were carried on.

8. Archaic. a fortress or stockade.

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barrier British  

/ ˈbærɪə /

noun

1. anything serving to obstruct passage or to maintain separation, such as a fence or gate

2. anything that prevents or obstructs passage, access, or progress

   a barrier of distrust

3. anything that separates or hinders union

   a language barrier

4. 1. an exposed offshore sand bar separated from the shore by a lagoon

   2. ( as modifier )

      a barrier beach

5. (sometimes capital) that part of the Antarctic icecap extending over the sea

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Related Words

See bar ¹.

Etymology

Origin of barrier

First recorded in 1275–1325; Middle English, from Middle French barriere ( barre bar ¹ + -iere, from Latin -āria -ary ); replacing Middle English barrere, from Anglo-French, from Medieval Latin barrera

Explanation

Barriers are walls, either physical or metaphorical. They can block movement — the Great Wall of China was a barrier to block invading forces from entering. A window shade is a light barrier. Failing English is a barrier to getting into Harvard. When people are being excluded from joining a clique, you could say that the clique has erected a social barrier. When fighter jets fly faster than the speed of sound, they break through what feels like a wall in the sky called the sound barrier. The Green Monster at Fenway Park keeps Boston Red Sox fans from being able to watch games from outside the stadium — it's a barrier to sight. But when line drives hit the Green Monster, bouncing the ball back into left field, the Green Monster acts also a barrier to easy home runs.

Example Sentences

Both the bus driver and the guard responsible for lowering the barrier - which is done manually - have also been charged, police said.

From BBC • May 18, 2026

Because these particles are so tiny, researchers are concerned they may pass through the intestinal barrier and build up in organs including the kidneys and brain.

From Science Daily • May 18, 2026

Other experimental technologies are also exploring ways to overcome this challenge, including ultrasound-based delivery systems, "brain shuttle" molecules, and additional nanoparticle platforms designed to cross the barrier more effectively.

From Science Daily • May 17, 2026

The adventurous nature of such sailings and the activities they provide can be riskier than a more traditional cruise and a barrier for people with certain physical limitations.

From The Wall Street Journal • May 17, 2026

After a lot of grunting, he rolled over the top of the four-foot-tall barrier.

From "Dog Squad" by Chris Grabenstein

Related Words

• barricade
• blockade
• boundary
• fence
• hurdle
• impediment
• limit
• obstacle
• railing
• roadblock
• wall