| Acronym | Definition |
|---|
| COS | Cost Of Sales |
| COS | Class Of Service |
| COS | Collection of Style (fashion line) |
| COS | Colorado Springs (Amtrak station code; Colorado Springs, CO) |
| COS | Chief of Staff |
| COS | Chamber of Secrets (book by J.K. Rowling) |
| COS | Commercial off the Shelf |
| COS | Cosine (mathematics) |
| COS | Conditions of Success |
| COS | Conditions of Satisfaction |
| COS | Church of Scientology |
| COS | Council of Students (various organizations) |
| COS | Consul (in ancient Rome) |
| COS | College of Security (Star Trek gaming) |
| COS | Children of Sin (song) |
| COS | Convention of States (Houston, TX) |
| COS | Charity Organization Society |
| COS | Cosinus |
| COS | Cosmetology |
| COS | Change Of Status |
| COS | Comite des Oeuvres Sociales (French: Committee of Social Works) |
| COS | Chance of Success (Oil and Gas) |
| COS | College of the Siskiyous (California) |
| COS | Chicks on Speed (band) |
| COS | Change of State |
| COS | Certificate of Sponsorship (UK) |
| COS | Committee on Sustainability (various locations) |
| COS | Controller of Stores (Indian railways) |
| COS | Certificate of Status (various locations) |
| COS | City of Saskatoon (Canada) |
| COS | Circle of Swords (gaming guild) |
| COS | Collège Ostéopathique Sutherland (French osteopathic college) |
| COS | Change Of Subject |
| COS | Contingency Operating Site (Iraq) |
| COS | Carnival of Space (blogging) |
| COS | Coefficient d'Occupation des Sols (French: Coefficient of Land Use) |
| COS | Conditions of Service |
| COS | Continued Operational Safety (aviation) |
| COS | Church Of Satan |
| COS | Credit Ombudsman Service (dispute resolution; Australia) |
| COS | Configuration Object Set |
| COS | Crypto Operating System |
| COS | Communications System |
| COS | Common Operations Services |
| COS | Clip on Socket |
| COS | Commercial Operating System |
| COS | Cassette Operating System |
| COS | Control System |
| COS | Cosine |
| COS | Corporation of Open Systems |
| COS | Custom Operating System |
| COS | Corba Object Services |
| COS | Common Object Services |
| COS | Central Offices |
| COS | Church of Scotland |
| COS | Conservation Officer Service (Canada) |
| COS | Cosmic Origins Spectrograph |
| COS | Cost of Service |
| COS | Cooperation for Open Systems (Internet) |
| COS | Centre d'Orientation Scolaire (French: School Counseling Center) |
| COS | Commandement des Opérations Spéciales (French: Special Operations Command) |
| COS | Conspiracy of Silence (gaming clan) |
| COS | Certificate Of Service |
| COS | Carbonyl Sulphide |
| COS | Cone of Silence (Get Smart; 1960s TV series) |
| COS | Code of Silence |
| COS | Canadian Ophthalmological Society |
| COS | Center for Operations Support |
| COS | Corporation for Open Systems |
| COS | Certificate of Suitability (European Directorate for the Quality of Medicines Agency; Council of Europe; France) |
| COS | Continuity of Service |
| COS | Change Of Station |
| COS | Card Operating System |
| COS | Corps Support |
| COS | Chief of Station (CIA) |
| COS | Compulsory Open Space (construction regulation; various locations) |
| COS | Chip Operating System |
| COS | Compatible Operating System |
| COS | Console Operating System (NASA) |
| COS | Chimie Organique de Synthèse (French: Synthetic Organic Chemistry) |
| COS | Close of Service (Peace Corps) |
| COS | Chief of General Staff (Israel) |
| COS | Common Operating System |
| COS | Center for Okinawan Studies (University of Hawaii at Manoa) |
| COS | Certified Occupancy Specialist (housing industry) |
| COS | Community Outreach Service (various locations) |
| COS | Critical Occupational Specialty (US DoD) |
| COS | Chicago Ornithological Society (Chicago, IL) |
| COS | Cloak of Shadows (World of Warcraft, gaming) |
| COS | Centre for Oxfordshire Studies (UK) |
| COS | Cray Operating System |
| COS | Club Olympique de Sartrouville (French martial arts club) |
| COS | Combinatorial Object Server |
| COS | Colectivo de Organizaciones Sociales (Spanish, Guatemala) |
| COS | Client Operating System |
| COS | Career Opportunity System |
| COS | Connection-Oriented Service |
| COS | Categories of Service (Medicaid) |
| COS | Continuity of Supply |
| COS | Culling of Stratholme (World of Warcraft; gaming) |
| COS | Caress of Steel (Rush album) |
| COS | Church Of the Savior |
| COS | Communications Segment |
| COS | Contrat d'Objectifs Scolaires (French: Educational Objectives Contract) |
| COS | Columbia Online Style |
| COS | Chip on Submount |
| COS | China Oilfield Services Ltd |
| COS | Cast-On Strap (battery manufacturing) |
| COS | Carrier Operated Squelch (two-way radio) |
| COS | Central Operating System (X-Files) |
| COS | Common Object Service |
| COS | CORBA Service |
| COS | Change Over Switch |
| COS | Combat Operations Squadron |
| COS | City of Sails (Barbershop Chorus, Auckland, New Zealand) |
| COS | Chief of Safety |
| COS | Conservative Opportunity Society |
| COS | Chief of Supply |
| COS | Client Online Services (various businesses) |
| COS | Cadet Officer School |
| COS | Cohesive End Site (bacteriophages) |
| COS | Cash On Shipment |
| COS | Canadian Oncology Society |
| COS | Committee on Specifications (AISI) |
| COS | Coronary Obstructive Syndrome |
| COS | Complete Orthonormal System |
| COS | Customer of Size (overweight passenger requiring two economy-class airline seats) |
| COS | Colorado Springs, CO, USA - Colorado Springs Municipal (Airport Code) |
| COS | Code Operated Switch |
| COS | Capital Outlay Support |
| COS | Come On Spring |
| COS | Company Orderly Sergeant |
| COS | Cult of Slaanesh (gaming, Warhammer) |
| COS | Corona Oxide Semiconductor |
| COS | Check on-Site |
| COS | Chiefs of Service (hospitals) |
| COS | Campus Outreach Services (St. Davids, PA) |
| COS | Chamber Orchestra of the Springs (Colorado Springs, CO) |
| COS | Condition of Supply (aerospace) |
| COS | Cell Output Switch |
| COS | Canadian Organic Standard |
| COS | Carry-On Oxygen System (NASA) |
| COS | Current Operations Section |
| COS | Coalition for Orchid Species |
| COS | Caked on Stripes (podcast) |
| COS | Civilian Occupational Specialty |
| COS | Customer Order System |
| COS | Casualty of Sound (Maniacal Plan music CD) |
| COS | Call Originate Status |
| COS | Computer On Silicon |
| COS | Co-Orbiting Satellite (NASA) |
| COS | Convergent Operating System (Mariposa Technology) |
| COS | Chemical Operation Specialist |
| COS | Chosen of Solclaim (gaming clan) |
| COS | Critical Operational Specialties |
| COS | Citizens for Open Space (various locations) |
| COS | Care Outreach Specialist (social work) |
| COS | Change of Subscriber |
| COS | Conference and Office Services |
| COS | Center For Obesity Surgery |
| COS | Component Oversight |
| COS | CO2 Removal Service |
| COS | Client Operating Server |
| COS | Customer's Own Stock (FedEx Kinko's) |
| COS | Community and Organizational Services |