[1] : The Collaborative International Dictionary of English v.0.48

tappet \tap"pet\, 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, a valve motion worked by tappets from a
      reciprocating part, without an eccentric or cam, -- used
      in steam pumps, etc.
      1913 webster
see also:
tappet motion 

[2] : WordNet (r) 2.0

tappet
     n : a lever that is moved in order to tap something else

Tappet >> T Words
Tappet, definition of term: Tappet
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