1 [count] : a position in which your knees are bent and your body lowered so that you are close to your heels or sitting on your heels
2 [noncount] US slang : the least amount : anything at all
I don't know squat [=diddly-squat] about baseball.
He didn't do squat all day.
The car is worth squat. [=nothing at all]
3 [count] chiefly British : an empty building that squatters live in
She lives in a squat.