[1] Organization Of American States

[2] One-to-All Scatter

[3] Office Automation System (->"NASA Acronym List")

[4] Orbiter Atmospheric/Aeroflight Simulator (->"NASA Acronym List") {Weltraumfahrt}

[5] Orbiter Avionics System (->"NASA Acronym List") {Weltraumfahrt}

[6] Oracle Application Server