Tappet
Pronunciation : Tap"pet
Part of Speech : n.
Definition : Defn: 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. Tappet motion, a valve motion worked by tappets from a reciprocating part, without an eccentric or cam, -- used in steam pumps, etc.
(Mach.)
Source : Webster's Unabridged Dictionary, 1913