end-port

Century Dictionary and Cyclopedia

1. n. In machinery: The opening at either end of the face of the valve-seat of a steam-engine, or the traverse of the valve thereon, through which steam is admitted alternately to the crank-end and to the head-end of the cylinder.
2. n. In gas-engines, an opening through the wall of the cylinder which is uncovered by the travel of the piston just as it reaches the end of its stroke. Such end-ports release the exhaust gases at the end of the stroke, particularly in the two-phase cycle type of engine.