back pressure valve

back Preposition

— Toward the rear. He went back behind the stands. — To a place again. I didn't like it, so I sent it back. He went back to the same house. They came back again.

back Noun

— The back is the rear part of something; it is the part in the other direction from the front. I went to the back of the house. — The back is the rear part of the human body. He had a scar on his back.

back Verb

— If you back something, you support it. The Republicans backed the bill. — If you back up, you move backward. He put the car in gear and backed right into the garage door.

pressure Noun

— In science, pressure is force applied over an area. It hurt when the doctor put pressure on her cut foot. He accidentally put too much air in his flat tire. The air put so much pressure on the tire that it exploded. — If a person is under pressure, they feel stressed. She has been under a lot of pressure lately because of her final exams. If she fails them, she will not graduate.

pressure Verb

— When you pressure someone, you try to make them do something, especially something they do not want to do. Her friends tried to pressure her into smoking, even after Maya kept saying "no." His parents tried to pressure him into becoming a lawyer, but Jamal knew he wanted to be a doctor.

valve Noun

— A valve is part of a tube that lets liquid or gas go through one way but stops it from going through the other way. There are four valves in the heart that let blood go in one direction but stop it from going in the other direction. — A valve is part of a tube that someone can open or close to let water or other things go through. Open this valve to let water go through the pipe.