Term: Jack Plate Image: [{"name":"images\/public\/dictionary\/Jack Plate_1cwtmq3y.jpg","usrName":"Jack Plate.jpg","size":271345,"type":"image\/jpeg","thumbnail":"images\/public\/dictionary\/thJack Plate_cax02hnh.jpg","thumbnail_type":"image\/jpeg","thumbnail_size":42230,"searchStr":"Jack Plate.jpg,!:sStrEnd"}] Definition: A mounting device for an outboard motor that enables operators to vertically raise or lower the motor, thereby controlling propeller depth in the water.