Chief Security Officer 
Central Services Organization 
Cognizant Security Office 
Caltech Submillimeter Observatory 
Central Statistical Office 
Central Statistics Office 
Cognizant Secretarial Officer 
Combined Sewer Overflow 
Competitive Sourcing Official 
Computing Services Office 
Connecticut Southern Railroad 
Chief Signal Officer 
Civil Society Organization 
Committee of Senior Officials 
Computer Security Officer 
computer security official 
CHAINED SEQUENTIAL OPERATION 
Civil Society Organizations 
Closely-Spaced Object 
Cognizant Security Offices 
Cold Start Only 
Combat Systems Officer 
Combine Sewer Overflow 
Combined Sewer Overflows 
Commissioners Standard Ordinary 
Communications Security Officer 
Communications Support Office 
communications support organization 
Community Service Office 
Community Service Offices