n. (Mach.) A lever or projection moved by some other piece, as a cam, or intended to tap or touch something else, with a view to produce change or regulate motion. G. Francis. [ 1913 Webster ]
Tappet motion,
. (Mech.) A rod carrying a tappet or tappets, as one for closing the valves in a Cornish pumping engine. [ Webster 1913 Suppl. ]