valve
noun [ C ] uk/vælv/ us/vælv/
阀;活门;（心脏或血管的）瓣膜
a device that opens and closes to control the flow of liquids or gases, or a similar structure in the heart and the veins that controls the flow of blood
The valve failed to open/close. 阀门打不开／关不上了。
It was a weak heart valve that caused her death. 是心瓣膜问题导致了她的死亡。
（喇叭等乐器的）阀键，活塞
part of a musical instrument such as a trumpet that changes the sound by controlling the flow of air