Orifice

An orifice is any opening, mouth, hole or vent, as in a pipe, a plate, or a body


 * Body orifice, any opening in the body of a human or animal
 * Orifice plate, a restriction used to measure flow or to control pressure or flow, sometimes given specialised names:
 * Calibrated orifice, used to control pressure or flow
 * Restrictive flow orifice, used to control flow
 * Miss Shilling's orifice, used to control flow in the engines of early Spitfire and Hurricane fighter aeroplanes
 * Back Orifice, a controversial computer program designed for remote system administration