0 to be in a position with the weight of your body on your bottom and the top part of your body up, for example, on a chair -- estar sentado
1 to move your body into a sitting position after you have been standing -- sentarse
She sat down on the grass.
2 to take an exam -- presentarse a
3 to be in a position on a seat or the ground with your back upright -- sentarse
4 to put yourself or sb else in a sitting position -- sentarse
5 (of an object) to be in a particular place or position -- estar