a sliding rod in an engine or machine moved by intermittent contact with a cam and used to move another part, as a valve
Origin of tappettap + -et
A lever or projecting arm that moves or is moved by contact with another part, usually to transmit motion, as between a driving mechanism and a valve.
Origin of tappetProbably from tap1.
- A lever or projection which is moved by some other piece, as a cam, or intended to tap or touch something else, in order to produce change or regulate motion.
From tap +"Ž -et, possibly influenced by homophony with "tap it."