a very narrow space between two things or two parts of something
He squeezed into a crack between two rocks.
He could see them through a crack in the door.
She opened the door a crack and peeped into the room.
a thin line on the surface of something when it is broken but has not actually come apart
There were several small cracks in the glass.
a weakness or fault in an idea, system, or organization
The cracks in their relationship were starting to show.
The first cracks are beginning to appear in the economic policy.
a sudden loud sound like the sound of a stick being broken
There was a sharp crack as the branch broke off.
We could hear the crack of gunfire in the distance.
a crack of thunder
a clever joke or rude remark
I didn't like his crack about her being overweight.
He's always making cracks about how stupid I am.
an attempt to do something [= shot]
I'd like a crack at climbing that mountain.
The competition's open to anyone - why don't you have a crack?
an illegal drug that some people take for pleasure:
the space between someone's buttocks
a hard hit on the head:
You've had a nasty crack on the head and you need to rest.
a change in someone's voice because they are feeling very upset:
He noticed the crack in her voice as she tried to continue.
very early in the morning
at the crack of dawn
We were up at the crack of dawn.
a piece of information or computer code that lets you illegally change free software which may lack certain features of the full version, so that the free software works in the same way as the full version