Dictionary.net

(Or "escape code") A series of characters startingwith the escape character (ASCII 27). Escape sequences areoften used to control display devices such as VDUs. Anescape sequence might change the colour of subsequent text,reassign keys on the keyboard, change printer settings orreposition the cursor. The escape sequences of the DECvt100 video terminal have become a de facto standard forthis purpose.The term is also used for any sequence of characters thattemporarily suspends normal processing of a stream ofcharacters to perform some special function. For example, theHayes modem uses the sequence "+++" to escape to commandmode in which characters are interpreted as commands to themodem itself rather than as data to pass through.[Was the character named after this use or vice versa?]