orifice, opening, porta (noun)

an aperture or hole that opens into a bodily cavity

"the orifice into the aorta from the lower left chamber of the heart"

orifice (Noun)

A mouth or aperture, as of a tube, pipe, etc.; an opening; as,

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