What does OS stand for?

What does OS mean?

OS	Oh Starcraft Miscellaneous » Science Fiction
OS	Overtly Similar Governmental » Military
OS	Ophiological Services Miscellaneous » Unclassified
OS	On Serotta Miscellaneous » Unclassified
OS	Ole Syversen Miscellaneous » Names and Nicknames
OS	Old Shinola Miscellaneous » Funnies
OS	Osteogenic Sarcoma (bone tumors) Medical » Oncology
OS	Omnipotent Spirituality Miscellaneous » Unclassified
OS	Occulus Sinister Miscellaneous » Unclassified
OS	Oooh Shizzit Miscellaneous » Unclassified
OS	Old Suisun Miscellaneous » Unclassified
OS	Outer Sen Miscellaneous » Unclassified
OS	A Outside System Miscellaneous » Unclassified
OS	Offentlig Sak Miscellaneous » Hobbies
OS	Operational Sponge Miscellaneous » Unclassified
OS	A On Surveillance Miscellaneous » Unclassified
OS	Open Space Academic & Science » Architecture
OS	Omega Strain Miscellaneous » Unclassified
OS	On Steroids Miscellaneous » Unclassified
OS	Ostrich Source Miscellaneous » Unclassified
OS	Orthopaedic Surgeon Miscellaneous » Unclassified
OS	Orzya Sativa Academic & Science » Botany
OS	Orbiter Specification Governmental » NASA
OS	Orbital Servicing Governmental » NASA
OS	Optics Subsystem Governmental » NASA