jacktop

plural jacktops

1. The top of a jack.

   A small butterfly spring between the side of the jacktop and the hammer butt replaces the familiar spring under the jack heel.

   1989, Piano Technician's Journal - Volume 32, page 5

   2 more examples

   The links should be provided with flexible leads which can be plugged into a pair of jacktop insulators mounted near the coil jack strip.

   1952, The Radio Amateur's Handbook - Volume 29, page 329

   For general laboratory use output may be taken from four insulated jacktop terminals on standard 3 in. spacing mounted on the front.

   1960, Laboratory Practice, page 259