Di‐rect″–act′ing (?), a.(Mach.) Acting directly, as one part upon another, without the intervention of other working parts.
Direct-acting steam engine, one in which motion is transmitted to the crank without the intervention of a beam or lever; — also called direct-action steam engine. — Direct-acting steam pump, one in which the steam piston rod is directly connected with the pump rod; — also called direct-action steam pump.