a long, narrow piece of metal that you slide across the inside of a door or window in order to lock it （门窗的）闩，插销 
He slid back the bolt on the door. 他拉开了门上的插销。
Oxford Collocations Dictionaryverb + bolt- draw back
- pull back
- slide back
- …
a piece of metal like a thick nail without a point which is used with a circle of metal (= a nut) to fasten things together 螺栓 nuts and bolts 螺帽和螺栓
Oxford Collocations Dictionaryverb + bolt- tighten
- tighten up
- loosen
- …
- nuts and bolts
- bolt of lightning
a sudden flash of lightning in the sky, appearing as a line 闪电 a short heavy arrow shot from a crossbow 弩箭 a long piece of cloth wound in a roll around a piece of cardboard 一匹（布）
Word Originnoun senses 1 to 4 Old English, ‘arrow’, of unknown origin; related to Dutch bout and German Bolzen ‘arrow, bolt for a door’. noun sense 5 Middle English: transferred use of bolt ‘metal pin’.
Idioms
a bolt from the blue
have shot your bolt
- (informal)
to have used all your power, money or supplies 竭尽全力；倾其所有
make a bolt for something | make a bolt for it
to run away very fast, in order to escape 迅速逃跑；溜走 The pony suddenly made a bolt for freedom. 小马突然奔向自由。
the nuts and bolts (of something)
- (informal)
the basic practical details of a subject or an activity 基本要点 The documentary focuses on the real nuts and bolts of the film-making process. 这个纪录片关注的是电影拍摄过程中的具体细节。