An orifice is any opening,

mouth In animal anatomy, the mouth, also known as the oral cavity, or in Latin cavum oris, is the opening through which many animals take in food and issue vocal sounds. It is also the cavity lying at the upper end of the alimentary canal, bounded on ...

, hole or vent, as in a pipe, a plate, or a body *

Body orifice A body orifice is any opening in the body of an animal. External In a typical mammalian body such as the human body, the external body orifices are: * The nostrils, for breathing and the associated sense of smell * The mouth, for eating, bre ...

, any opening in the body of a human or animal *

Orifice plate An orifice plate is a device used for measuring flow rate, for reducing pressure or for restricting flow (in the latter two cases it is often called a '). Description An orifice plate is a thin plate with a hole in it, which is usually placed in ...

, a restriction used to measure flow or to control pressure or flow, sometimes given specialised names: **

Calibrated orifice An orifice plate is a device used for measuring flow rate, for reducing pressure or for restricting flow (in the latter two cases it is often called a '). Description An orifice plate is a thin plate with a hole in it, which is usually placed in ...

, used to control pressure or flow **

Restrictive flow orifice A Restrictive Flow Orifice (RFO) is a type of orifice plate. They are used to limit the potential danger, damage, or wastage of an uncontrolled flow from, for example, a compressed gas cylinder They are generally not limiting the flow during normal ...

, used to control flow **

Miss Shilling's orifice Miss Shilling's orifice was a very simple technical device made to counter engine cut-out in early Spitfire and Hurricane fighter aeroplanes during the Battle of Britain. While it was officially called the R.A.E. restrictor, it was referred to ...

, used to control flow in the engines of early Spitfire and Hurricane fighter aeroplanes *

Back Orifice Back Orifice (often shortened to BO) is a computer program designed for remote administration, remote system administration. It enables a user to control a computer running the Microsoft Windows operating system from a remote location.Richtel, M ...

, a controversial computer program designed for remote system administration

See also