noun
A person or organisation that operates a device, system, service, etc.
A telecommunications facilitator whose job is to connect or otherwise assist callers.
A member of a military special operations unit.
(uncountable) The game of Chinese whispers.
(informal) A person who is adept at making deals or getting results, especially one who uses questionable methods.
(mathematics) A function or other mapping that carries values defined on a domain into another value or set of values in a defined range.
(computing) The administrator of a channel or network on IRC.
(computing) A symbol that represents a construct in a programming language and differs from a normal function in its syntax.
(linguistics) A kind of expression that enters into an a-bar movement dependency and is said to bind a variable.
(transport) A bus driver.
(by ellipsis, mining) The company that operates a mine; often the same one that owns the mine.
(slang) A thief or charlatan.
(slang) A major criminal.
(slang, dated) Someone who is successful at pursuing women; a player.