\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}.