| Acronym | Definition |
|---|
| CSO | Chief Security Officer (corporate title) |
| CSO | Combined Sewer Overflow |
| CSO | Computer Security Officer |
| CSO | Cincinnati Symphony Orchestra. |
| CSO | Civil Society Organization |
| CSO | Columbus Symphony Orchestra (Columbus, GA) |
| CSO | Computational Sciences and Optimization |
| CSO | Chief Strategy Officer (corporate title) |
| CSO | Centre de Sociologie des Organisations |
| CSO | Colorado Symphony Orchestra |
| CSO | Contract Sales Organization |
| CSO | Community Service Officer (law enforcement) |
| CSO | Company Security Officer |
| CSO | Committee of Senior Officials |
| CSO | Customer Service Officer |
| CSO | Czech Statistical Office |
| CSO | Community Service Obligation |
| CSO | Composite Second-Order (distortion) |
| CSO | Community Support Officer |
| CSO | Commissioners Standard Ordinary (insurance mortality tables) |
| CSO | Customer Service Organization |
| CSO | Consumer Safety Officer |
| CSO | Combat Systems Officer |
| CSO | Community Services Officer |
| CSO | Charlotte Symphony Orchestra |
| CSO | Competitive Sourcing Official |
| CSO | Colour Separation Overlay (Chroma-Key) |
| CSO | Connecticut Southern (railroad) |
| CSO | Corporate Social Opportunity |
| CSO | Customer Support Office |
| CSO | Concours de Saut d'Obstacle (France) |
| CSO | Construction Safety Officer (Canada) |
| CSO | Child Support Order |
| CSO | Court Services Officer |
| CSO | Child Support Officer |
| CSO | Centre Social Okupat |
| CSO | Cognizant Security Office |
| CSO | Christian Science Organization |
| CSO | Center for Student Opportunity (Bethesda, MD) |
| CSO | Child Support Obligation |
| CSO | Cobb Symphony Orchestra (Marietta, Georgia) |
| CSO | Compact Symmetric Object |
| CSO | Client Services Office |
| CSO | Customer Special Order |
| CSO | Citizens Support Organization |
| CSO | Customer Service and Operations |
| CSO | Computer Surplus Outlet |
| CSO | Caretaker Site Office (US Navy) |
| CSO | Closely-Spaced Object |
| CSO | Compensated Sapphire Oscillator |
| CSO | Car-Seal Open (valve condition) |
| CSO | Catholic Students Organization |
| CSO | Craniostenosis |
| CSO | Custom Scenery Object (aka Custom Scenery; also seen as CS; Atari) |
| CSO | Clinical Support Officer |
| CSO | Chief Suitability Officer (corporate title) |
| CSO | Campus Service Officer |
| CSO | Collateralised Synthetic Obligation |
| CSO | Computer System Operator |
| CSO | Command Security Officer |
| CSO | Commissary Officer |
| CSO | Concurrent Servicing Operations |
| CSO | Cadet Second Officer |
| CSO | Compulsory Stock Obligation (UK fuel tax) |
| CSO | Communications-Computer Systems Officer |
| CSO | Customer Satisfaction Opportunity |
| CSO | Client Support Operations |
| CSO | Curvature of the Second Order |
| CSO | Composite Signals Organization |
| CSO | Chandler Symphony Orchestra (Chandler, AZ) |
| CSO | Copper-Sensitive Operon |
| CSO | Communication Service Order |
| CSO | Collateral Security Obligation |
| CSO | Commercial Solicitation Officer |
| CSO | Constant Scheduling Offset |
| CSO | Combat Systems Operations (AMSEC) |
| CSO | Claim Service Office (Insurance) |
| CSO | Cheerfully Start Over |
| CSO | Centralized Sellers Office |
| CSO | Crowthorne Symphony Orchestra (UK) |
| CSO | Central Services Office(Montana) |
| CSO | Central Statistical Organisation (Delhi, India) |
| CSO | Chief Sales Officer (corporate title) |
| CSO | Central Seismological Observatory (India) |
| CSO | Chief Signal Officer |
| CSO | Clinical Skills Online (UK) |
| CSO | Communications Support Organization (US DoD) |
| CSO | Catholics Speak Out |
| CSO | Conservatoire Supérieur d'Ostéopathie (French: Superior Conservatory of Osteopathy) |
| CSO | Center for Special Operations (USSO COM) |
| CSO | Centre Subaquatique Orléanais (French diving club) |
| CSO | Campus Security Officer |
| CSO | Cap Sud Ouest (French employment agency) |
| CSO | Central Selling Organization (diamond industry) |
| CSO | Chief Scientist Office (Scottish Government Health Directorates; UK) |
| CSO | Car Sharing Organization |
| CSO | Club Subaquatique d'Onex (French diving club) |
| CSO | Certified Specialist in Oncology Nutrition |
| CSO | Chief Solutions Officer (corporate title) |
| CSO | Chief Scientific Officer (corporate title) |
| CSO | Campus Safety Officer |
| CSO | Consulting Services Organization |
| CSO | Chief Staff Officer |
| CSO | Central Services Organization |
| CSO | Central Statistical Office (UK Government Office) |
| CSO | Chicago Symphony Orchestra |
| CSO | Caltech Submillimeter Observatory |
| CSO | Central Statistics Office (Ireland) |