PETSCII: /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,

:PETSCII: /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.
-- The AI Hackers Dictionary