OAO explained

OAO, a three-letter acronym, may stand for:

• Orbiting Astronomical Observatory, the name of four NASA scientific satellites
• Open joint-stock company (Russian: '''О'''ткрытое '''A'''кционерное '''O'''бщество|link=no), business incorporation in Russia, Ukraine etc.
• Odessey and Oracle, 1968 album by The Zombies
• a platform game made by Oddworld Inhabitants released in 1997
• Over and Out (disambiguation), various meanings including the usual ending of transmissions in telecommunications
• Open-access operator, a British passenger rail company which does not hold a franchise