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

I remember thinking that wealth is a great barrier to harm and then feeling silly for extrapolating my own experience once again.

From Los Angeles Times • Apr. 24, 2026

"The consumed soil acts as a barrier in the digestive tract, limiting absorption of harmful compounds."

From BBC • Apr. 22, 2026

In the past, it was very difficult to run a business on your own, she said, but the range of tasks that AI can help with has "lowered the entry barrier".

From Barron's • Apr. 22, 2026

This substance acts as a protective barrier for tumors by slowing down T cells and preventing them from entering cancerous tissue.

From Science Daily • Apr. 21, 2026

And I stood there, my arms raised like a barrier, with my teeth bared and a ferocious expression on my face.

From "Ida B" by Katherine Hannigan

Related Words

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