jump seat
    n 1: a folding seat in an automobile

Jump \Jump\, n.
   1. The act of jumping; a leap; a spring; a bound. "To advance
      by jumps." --Locke.
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   2. An effort; an attempt; a venture. [Obs.]
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            Our fortune lies
            Upon thisjump.                        --Shak.
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   3. The space traversed by a leap.
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   4. (Mining) A dislocation in a stratum; a fault.
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   5. (Arch.) An abrupt interruption of level in a piece of
      brickwork or masonry.
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   6. A jump-start; as, to get a jump from a passing mmotorist.
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   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.
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