Source : Webster's Revised Unabridged Dictionary (1913)

Trispast \Tri"spast\, Trispaston \Tri*spas"ton\, n. [NL.
   trispaston, fr. Gr. ? drawn threefold; ? (see {Tri-}) + ? to
   draw.] (Mech.)
   A machine with three pulleys which act together for raising
   great weights. --Brande & C.