[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 

Motion >> M Words
Motion, definition of term: Motion
motion_pag1.html

Tappet >> T Words
Tappet, definition of term: Tappet
tappet_pag1.html

Motion Sickness >> M Words
Motion Sickness, definition of term: Motion Sickness
motion+sickness_pag1.html

Motion Picture >> M Words
Motion Picture, definition of term: Motion Picture
motion+picture_pag1.html

Brownian Motion >> B Words
Brownian Motion, definition of term: Brownian Motion
brownian+motion_pag1.html

Uniform Motion >> U Words
Uniform Motion, definition of term: Uniform Motion
uniform+motion_pag1.html

Law Of Motion >> L Words
Law Of Motion, definition of term: Law Of Motion
law+of+motion_pag1.html