| C/S/O | Cross Streets Off 
| Others |
| CSO | C Shared Object
| Others |
| CSO | Caltech Submillimeter Observatory
| Others |
| CSO | Campus Safety Officers
| Others |
| CSO | Campus Service Officer
| Others |
| CSO | Canberra Symphony Orchestra
| Others |
| CSO | Car Sales Organizer
| Others |
| CSO | Car Seal Open
| Others |
| CSO | Car Seat Only
| Others |
| CSO | Car Software Organisation
| Others |
| CSO | Career Services Office
| Others |
| CSO | Career Services Online
| Others |
| CSO | Casetrack Support Officer
| Others |
| CSO | Celebrity Scratch Off
| Others |
| CSO | Center for Science Outreach
| Others |
| CSO | Center for Special Operations
| Others |
| CSO | Central Services Organization
| Others |
| CSO | Central States of Omaha
| Others |
| CSO | Central Statistic Office
| Others |
| CSO | Central Statistical Office
| Others |
| CSO | Central Statistical Organisation
| Others |
| CSO | Central Statistical Organization
| Others |
| CSO | Central Statistics Office
| Agency, Government |
| CSO | Central Statistics Ofice
| Others |
| CSO | Central Statistics Organization
| Others |
| CSO | Central Student Outreach
| Others |
| CSO | Central Susquehanna Opportunities
| Others |
| CSO | Charleston Symphony Orchestra
| Others |
| CSO | Charlotte Symphony Orchestra
| Others |
| CSO | Charter Schools Office
| Others |
| CSO | Chartered Student Organizations
| Others |
| CSO | Chattanooga Symphony Orchestra
| Others |
| CSO | Chicago Symphony Orchestra
| Others |
| CSO | Chief Safety Officer
| Others |
| CSO | Chief Sales Officer
| Others |
| CSO | Chief Scapegoat Officer
| Others |
| CSO | Chief Scientific Officer
| Others |
| CSO | Chief Scientist Office
| Others |
| CSO | Chief Security Officer
| Others |
| CSO | Chief Services Officer
| Others |
| CSO | Chief Signal Officer
| Others |
| CSO | Chief Strategy Officer
| Others |
| CSO | Chief Stress Officer
| Others |
| CSO | Chief Sustainability Officer
| Others |
| CSO | Chief Sustainability Officers
| Others |
| CSO | Chlamydia Screening Office
| Others |
| CSO | Christchurch Symphony Orchestra
| Others |
| CSO | Christian Science Organization
| Others |
| CSO | Christian Science Organizations
| Others |
| CSO | Cincinnati Symphony Orchestra
| Others |
| CSO | Citizen Support Organization
| Others |
| CSO | Civil Society Organisation
| Others |
| CSO | Civil Society Organisations
| Others |
| CSO | Civil Society Organization
| Others |
| CSO | Civil society organizations
| Others |
| CSO | Cleveland Symphony Orchestra
| Others |
| CSO | Clinical and Support Options
| Others |
| CSO | Clinical Support Options
| Others |
| CSO | Closely-Spaced Objects
| Others |
| CSO | Cloud Service Offering
| Others |
| CSO | Club Safeguarding Officer
| Others |
| CSO | Cluster Supporting Object
| Others |
| CSO | Coastal States Organization
| Others |
| CSO | Coated Side Out
| Others |
| CSO | Cognizant Security Office
| Others |
| CSO | Collaboration Support Office
| Others |
| CSO | College of Syntonic Optometry
| Others |
| CSO | Colonial Secretary's Office
| Others |
| CSO | Color Separation Overlay
| Others |
| CSO | Colorado Symphony Orchestra
| Others |
| CSO | Colour Separation Overlay
| Others |
| CSO | Columbia Symphony Orchestra
| Others |
| CSO | Columbus Symphony Orchestra
| Others |
| CSO | Combat Systems Officer
| Others |
| CSO | Combat Systems Officers
| Others |
| CSO | Combined Sewage Overflow
| Others |
| CSO | Combined Sewer Outflow
| Others |
| CSO | Combined Sewer Overflow
| Others |
| CSO | Combined Sewer Overflows
| Others |
| CSO | Commercial Solutions Opening
| Others |
| CSO | Commercial Stakeholder Organisation
| Others |
| CSO | Commissioners Standard Ordinary
| Others |
| CSO | Common Scientific Outline
| Others |
| CSO | Common Source Outbreak
| Others |
| CSO | Communications Service Order
| Others |
| CSO | Communications Support Organization
| Others |
| CSO | Community School Organization
| Others |
| CSO | Community Service Office
| Others |
| CSO | Community Service Officer
| Others |
| CSO | Community Service Officers
| Others |
| CSO | Community Service Order
| Others |
| CSO | Community Service Organization
| Others |
| CSO | Community Services of Oakland
| Others |
| CSO | Community Services of Oakland County, Michigan
| Others |
| CSO | Community Services Office
| Others |
| CSO | Community Services Offices
| Others |
| CSO | Community Snow Observations
| Others |
| CSO | Community Support Officer
| Others |
| CSO | Components and Supply Operations
| Others |
| CSO | Composite Second Order
| Others |
| CSO | Composite Second Order Beat
| Others |
| CSO | Compressed ISO file
| Others |
| CSO | Computer Security Officer
| Others |
| CSO | Computer Security Official
| Others |
| CSO | Computer Service Organization
| Others |
| CSO | Computer Systems Operation
| Others |
| CSO | Computing Services Office
| Others |
| CSO | Conflict and Stabilization Operations
| Others |
| CSO | Connecticut Southern Railroad
| Others |
| CSO | Construction Safety Officer
| Others |
| CSO | Consumer Safety Officer
| Others |
| CSO | Content Standards and Objectives
| Others |
| CSO | Contour Segmentation Objects
| Others |
| CSO | Contract Standing Order
| Others |
| CSO | Correct Solution Only
| Others |
| CSO | Correct Solutions Only
| Others |
| CSO | Council for Student Organizations
| Others |
| CSO | Counter-Strike Online
| Others |
| CSO | Court Security Officer
| Others |
| CSO | Court Service Online
| Others |
| CSO | Court Services Officer
| Others |
| CSO | Credit Services Organization
| Others |
| CSO | Credit Services Organizations
| Others |
| CSO | Cumhurbaskanligi Senfoni Orkestrasi
| Others |
| CSO | Customer Service Officer
| Others |
| CSO | Customer Service Officers
| Others |
| CSO | Customer Service Operations
| Others |
| CSO | Customer Service Order
| Others |
| CSO | Customer Services Officer
| Others |
| CSO | Customer Solutions Online
| Others |
| CSO | Customer Support Officer
| Others |
| CSO | Customer Support Organization
| Others |
| CSO | Cyber Security Operations
| Others |
| CSO | Cycles since Overhaul
| Others |
| CSO | Cylinder Shut Off
| Others |
| CSO | Czech Statistical Office
| Others |
| CSO | Magdeburg-Cochstedt Airport
| Others |