- resembling a jack rabbit, as in suddenness or rapidity of movement: The car made a jackrabbit start when the traffic light turned green.
- to go or start forward with a rapid, sudden movement.
- any of various large hares of western North America, having very long hind legs and long ears.
- any of various W North American hares, such as Lepus townsendi (white-tailed jack rabbit), having long hind legs and large ears
