One who operates.

A telecommunications facilitator whose job is to establish temporary network connections.

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 variables defined on a domain into another variable or set of variables 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.

(slang) A thief or charlatan.

(slang) A major criminal.