Commonwealth of Independent States 
Combat Intelligence System 
Clinical Information System 
Center for Internet Security 
Central Index System 
CompuServe Information Service 
Combat Information System 
Combat Intelligence Systems 
Cancer Information Service 
Card Information Structure 
Computer Information Systems 
configuration items 
Citizenship and Immigration Services 
Cluster Ion Spectrometry 
Communications and Information Systems 
Canadian Ice Service 
Combat Identification System 
Corporate Information System 
Customer Information System 
Chemical Information System 
Client Information System 
Combat Instruction Set 
Communications Interface Shelter 
Component Identification Sheet 
Compuserve Information Systems 
Consumer Information Source 
Contact Image Sensor 
Contractor's Information Submittal 
Cryogenic Interferometer/Spectrometer 
Customized Intercept Service