| Acronym | Definition |
|---|
| OSA➣Obstructive Sleep Apnea |
| OSA➣Optical Society of America |
| OSA➣Office of the State Auditor |
| OSA➣Office of Student Affairs |
| OSA➣Osteosarcoma (tumors) |
| OSA➣Office of Student Activities (various schools) |
| OSA➣Office of Special Affairs (Church of Scientology International) |
| OSA➣Oakland School for the Arts (California) |
| OSA➣On Shelf Availability (of products in a store) |
| OSA➣Operational Support & Analysis (Information Technology Infrastructure Library) |
| OSA➣Office of Substance Abuse |
| OSA➣Office of Services to the Aging (Michigan) |
| OSA➣Operation Save America (aka Operation Rescue; anti-abortion group) |
| OSA➣Out of Service Area |
| OSA➣Out of Band Services Architecture |
| OSA➣Optical Subassembly |
| OSA➣Open Systems Adapter |
| OSA➣Open System Authentication |
| OSA➣Open Solutions Alliance |
| OSA➣Open Scripting Architecture |
| OSA➣Object Storage Architecture |
| OSA➣Oracle Sales Analyser |
| OSA➣Open System Architecture |
| OSA➣Open Services Architecture |
| OSA➣Open Service Access |
| OSA➣Operational Support Area |
| OSA➣Operating System Administrator |
| OSA➣Open Source Architecture |
| OSA➣Object Oriented Systems Analysis |
| OSA➣over Sampling |
| OSA➣Optical Spectrum Analyzer |
| OSA➣Outside Air |
| OSA➣Open Solutions Alliance (vendor consortium) |
| OSA➣Official Secrets Act |
| OSA➣Open Systems Architecture |
| OSA➣Open Society Archives (Budapest, Hungary) |
| OSA➣Oregon Student Association (est. 1975) |
| OSA➣Old Scholars' Association (various organizations) |
| OSA➣Overseas Subscribers Agents (lottery agent) |
| OSA➣Office of Student Achievement (various locations) |
| OSA➣Online Savings Account |
| OSA➣Oxford Spires Academy (UK) |
| OSA➣Open Service Access (3GPP) |
| OSA➣Operational Support Airlift (US DoD) |
| OSA➣Open Service Architecture |
| OSA➣Operating System Authentication |
| OSA➣Organizzazione degli Stati Americani |
| OSA➣Outstanding Service Award |
| OSA➣Operacion San Andres (Peruvian operation) |
| OSA➣Office of the Secretary of the Army |
| OSA➣Operational Support Aircraft |
| OSA➣Ordo Sancti Augustini (St Augustine Order) |
| OSA➣Order of Saint Augustine |
| OSA➣Open Software Associates |
| OSA➣Open Source Academy (various locations) |
| OSA➣Overseas Students' Association (University of Adelaide, Australia) |
| OSA➣Optical Subassemblies (Palomar Technologies) |
| OSA➣Old Stone Age (gaming forums) |
| OSA➣Organization of Staff Analysts (New York, NY) |
| OSA➣Optimal Shelf Availability |
| OSA➣Organización Sionista Argentina |
| OSA➣Opportunistic Spectrum Access |
| OSA➣Operations Support Assignment |
| OSA➣Oberstabsarzt (German military) |
| OSA➣Om Svar Anhålles |
| OSA➣Order of St Anne |
| OSA➣Oscilloquartz SA (Switzerland) |
| OSA➣Our Special Ale (Anchor Christmas Ale) |
| OSA➣Online Sexual Activity |
| OSA➣Organizations and Strategies in Astronomy |
| OSA➣Object Services Architecture |
| OSA➣Otto Schulze Autometer |
| OSA➣Open Security Architecture (Nortel) |
| OSA➣Orchid Society of Arizona (Phoenix, AZ) |
| OSA➣Operational Staging Area (various organizations) |
| OSA➣Ordinis Sancti Augustini (of the order of St Augustine) |
| OSA➣Open Solutions Architecture (Novell) |
| OSA➣Open Space Assessment |
| OSA➣Old Stock Ale (North Coast Brewery) |
| OSA➣Oregon Society of Anesthesiologists |
| OSA➣Opus Sanctorum Angelorum (Latin: Work of the Holy Angels; religious order) |
| OSA➣Office of Space Acquisition |
| OSA➣Oregon Soccer Association (Oregon, WI) |
| OSA➣Operational Support Authority |
| OSA➣Office of the Space Architect |
| OSA➣Olympic Science Alliance |
| OSA➣Outfitting Supply Activity |
| OSA➣Orbiter-based Station Avionics |
| OSA➣Office of Safety Appraisals |
| OSA➣Olentangy Swim Association (Powell, OH) |
| OSA➣Office Solution Accelerator (Microsoft) |
| OSA➣Out of Station Allowance |
| OSA➣Outfitting Support Activity |
| OSA➣Operational Safety Analysis/Assessment |
| OSA➣Objective Switching Architecture |
| OSA➣Hermits of St. Augustine, Augustinians (religious order) |
| OSA➣Operating System Account |
| OSA➣Ocala Sportsman's Association, Inc (Florida, USA) |
| OSA➣Optic Stabilizer Assembly |
| OSA➣Ontology Server for Archaeological Information Retrieval and Processing |
| OSA➣OPLAN Supportability Analysis |
| OSA➣observability subspace algorithm |
| OSA➣On-Screen Analysis |
| OSA➣Owatonna Soccer Association (Minnesota) |
| OSA➣Officially Step Aside |
| OSA➣Organización de Seguros Africanos (Spanish: African Insurance Organization) |
| OSA➣Online Selling Association (Hutchinson, KS) |