(1) A character whose occurrence in a particular context specifies a control function. . (2) A character, other than a graphic character, that affects the recording, processing, transmission, or interpretation of text. X/Open. See nonprinting character.
Any of the 32 ASCII characters that do not print on your screen or printer. These characters are usually used to control your computer.
a) [ISO] A control function, the coded representation of which consists of a single bit combination. b) [IBM] A character whose occurence in a particular context initiates, modifies, or stops a control function.