a solid or hollow figure with round ends and long straight sides 圆柱；圆柱体；圆筒 
an object like a cylinder in shape, especially one used as a container （尤指用作容器的）圆筒状物 a gas/oxygen cylinder 气罐；氧气瓶 All our aircraft carry at least one oxygen cylinder for emergency use on board. 我们每架飞机至少携带一只氧气瓶，以备机上急用。
the hollow tube in an engine, like a cylinder in shape, inside which the piston moves （发动机的）气缸 a six-cylinder engine 六缸发动机
Word Originlate 16th cent.: from Latin cylindrus, from Greek kulindros ‘roller’, from kulindein ‘to roll’.
Idioms
working/firing on all cylinders
- (informal)
using all your energy to do something; working as well as possible 竭尽全力；尽力干好；开足马力