@MontereyJack,
I agree with MontereyJack in terms of the action, but in terms of usage, you will often see the word 'squat' used in the context of exercise, as a 'squat' is a specific move but you will not see 'crouch' used in that context.
Someone might say, 'Do ten squats' which means to bend your knees and lower your bottom toward the floor.
They won't say though, 'Do ten crouches' even though it's basically the same movement and would work the same muscles.