Meaning of “crack” - Learner’s Dictionary

crack

verb uk us /kræk/
BREAK [ I, T ]

B2 to break something so that it does not separate, but very thin lines appear on its surface, or to become broken in this way:

Linda cracked her tooth when she fell.
The concrete had started to crack.
cracked dishes
EGG/NUT [ T ]

to open an egg or nut by breaking its shell

HIT [ T ]

to hit a part of your body against something hard, by accident:

He cracked his head on the shelf.
SOLVE [ T ] informal

to solve a difficult problem:

It took three months to crack the enemy's code.
get cracking informal

to start doing something quickly:

Let's get cracking! We've only got two days to finish.
LOSE CONTROL [ I ]

to lose control of your emotions and be unable to deal with a situation:

He finally cracked after years of stress.
NOISE [ I, T ]

to make a sudden, short noise, or to make something make this noise

crack a joke

to tell a joke

(Definition of “crack verb” from the Cambridge Learner’s Dictionary © Cambridge University Press)