The all-capitalized word GEOS may mean different things, depending on context. Among these are:

• GEOS (eikaiwa), a Japanese eikaiwa-type English language education company
• Graphic Environment Operating System, denoting two distinct GUI computer operating systems created by Berkeley Softworks, later Geoworks:
  • GEOS (8-bit operating system), for 6502-based home computers ("HC/GEOS"), primarily for the Commodore 64 and 128 and Apple II
  • GEOS (16-bit operating system), for IBM PC compatible desktop computers ("PC/GEOS") and x86-based smart phones and PDAs