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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Synonym Usage

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

High rocket-launch costs have historically been the key barrier to entry, and SpaceX has led the effort to make it cheaper to get into orbit with its Falcon 9.

From MarketWatch • Jun. 9, 2026

I had a late start, and by the time I reached the fence, the ball bounced off my glove and over the barrier for a grand-slam home run.

From The Wall Street Journal • Jun. 9, 2026

"Your skin barrier - which keeps toxins out and keeps moisture in - is beautifully preserved… That's youth, that's the beauty of skin."

From BBC • Jun. 6, 2026

He picked up some Spanish from Latino teammates in Japan that he uses to help bridge the language barrier.

From Los Angeles Times • Jun. 5, 2026

Someone had put down a thick barrier of salt just inside the door.

From "Ophie's Ghosts" by Justina Ireland

Related Words

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