GEOS may be:

• GEOS (eikaiwa), an Eikaiwa- company specialising in language education (usually English), based mainly in Japan
• Graphic Environment Operating System, denoting two distinct graphical user interface 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, for IBM PC compatible desktop computers and x86-based smart phones and PDAs
• GEOS (software) Geometrical Engine Open Source

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