1wall 
/ˈwɑ:l/ noun
plural walls /ˈwɑ:l/ noun [count] 1 : a structure of brick, stone, etc., that surrounds an area or separates one area from another
▪ A stone wall marks off their property. ▪ the Great Wall of China ▪ the walls of the ancient city — often used figuratively ▪ The wave was like a wall of water. ▪ The police formed a human wall around him. ▪ His suggestion was met with a wall of silence. [=was met with complete silence] ▪ a wall of sound ▪ He built an emotional wall [=barrier] around himself. — see also climbing wall, fire wall, retaining wall, seawall 2 : the structure that forms the side of a room or building
▪ She hung posters on the walls of her room. ▪ This apartment building has thin walls, and you can hear everything your neighbors say. ▪ A lot has happened inside these four walls. [=inside this room] ▪ Lower your voice and be careful what you say. The walls have ears. [=other people could be listening to what you say] 3 : the outer layer of something that is hollow (such as a part of the body or of a plant)
▪ plant cell walls ▪ Muscles in the abdominal wall help protect organs.
▪ A stone wall marks off their property. ▪ the Great Wall of China ▪ the walls of the ancient city — often used figuratively ▪ The wave was like a wall of water. ▪ The police formed a human wall around him. ▪ His suggestion was met with a wall of silence. [=was met with complete silence] ▪ a wall of sound ▪ He built an emotional wall [=barrier] around himself. — see also climbing wall, fire wall, retaining wall, seawall
▪ She hung posters on the walls of her room. ▪ This apartment building has thin walls, and you can hear everything your neighbors say. ▪ A lot has happened inside these four walls. [=inside this room] ▪ Lower your voice and be careful what you say. The walls have ears. [=other people could be listening to what you say]
▪ plant cell walls ▪ Muscles in the abdominal wall help protect organs.
back is to/against the wall — see 1back
climbing the walls — see 1climb
drive (someone) up a/the wall
informal : to make (someone) irritated, angry, or crazy
▪ Your constant tapping is driving me up the wall! ▪ Her voice drives me up a wall. [=her voice is very annoying to me]
▪ Your constant tapping is driving me up the wall! ▪ Her voice drives me up a wall. [=her voice is very annoying to me]
fly on the wall — see 3fly
go to the wall
informal 1 US : to make every possible effort to achieve something, to win, etc.
▪ He's prepared to go to the wall to defend his beliefs. 2 Brit : to fail because of a lack of money
▪ a company that has gone to the wall
▪ He's prepared to go to the wall to defend his beliefs.
▪ a company that has gone to the wall
hit a/the wall
informal : to reach a point at which you find it very difficult or impossible to continue
▪ He worked late every day and took frequent business trips for several years before he finally hit the wall. ▪ They seem to have hit the wall in terms of new ideas. ▪ Her tennis career hit a wall after the injury.
▪ He worked late every day and took frequent business trips for several years before he finally hit the wall. ▪ They seem to have hit the wall in terms of new ideas. ▪ Her tennis career hit a wall after the injury.
the writing/handwriting is on the wall or see/read the writing/handwriting on the wall
— used to say that it is clear that something bad will probably happen soon ▪ I haven't lost my job yet, but the writing is on the wall: my company just laid off 50 more people today. ▪ No one told him he was going to be fired, but he could see the writing on the wall.
up against a/the wall
informal : in a very bad position or situation
▪ The team was up against a wall in the first half of the game.
▪ The team was up against a wall in the first half of the game.
