/pet'skee/ [abbreviation of PET ASCII] n. The variation (many would say perversion) of the {ASCII} character set used by the Commodore Business Machines PET series of personal computers and the later Commodore C64, C16, and C128 machines. The PETSCII set used left-arrow and up-arrow (as in old-style ASCII) instead of underscore and caret, placed the unshifted alphabet at positions 65--90, put the shifted alphabet at positions 193--218, and added graphics characters.