Meaning of direct-acting

di•rect-act•ing

Pronunciation: (di-rekt'ak"ting, dī-), [key]
— adj.
  1. (of a steam pump) having the steam pistons connected directly to the pump pistons without a crankshaft or flywheel.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.