Jump, n.
1. The act of jumping; a leap; a spring; a bound. “To advance by jumps.”
2. An effort; an attempt; a venture. [Obs.]
Our fortune lies
Upon thisjump. --Shak.
3. The space traversed by a leap.
4. Mining A dislocation in a stratum; a fault.
5. Arch. An abrupt interruption of level in a piece of brickwork or masonry.
From the jump, from the start or beginning. [Colloq.]
Jump joint. (a) A butt joint. (b) A flush joint, as of plank in carvel-built vessels.
Jump seat. (a) A movable carriage seat. (b) A carriage constructed with a seat which may be shifted so as to make room for second or extra seat. Also used adjectively; as, a jump-seat wagon.
jump seat
n : a folding seat in an automobile