1) to be in, take, a position with one's body upright and one's bottom resting on the ground, a seat etc (sit)

2) an arched roof; series of arches forming a roof; an underground room used for storing things (e.g. a 'wine vault') or for keeping valuables ( a 'bank vault') or for dead bodies (e.g. under a church); to jump in a single movement, with the hand(s) resting on something, or with the help of a pole (vault)