Chief Administrative Officer 
CARRARO 
Center Adjudications Officer 
Contract Administration Office 
Computer-Assisted Ordering 
Calcium Oxide 
Central Accounting Office 
Compliance Advisor Ombudsman 
Computer Aided Office 
Computer-Aided Optimization 
Constant Administrative Office 
Corrective Action Order 
Counter Air Operation 
Canadian Association of Optometrists 
Canadian Association of Orthodontists 
Cargo Aircraft Only 
Carlsbad Area Office 
carotid artery occlusion 
Casualty Assistance Office 
Catania Astrophysical Observatory 
Central Aerological Observatory 
Central Application Office 
Central Applications Office 
Change of Appointing Office 
Chief Academic Officer 
Chief Acquisition Officers 
Chief Administrative Office 
Chief Agency Officer 
Chief Analytics Officer 
Chief Awareness Officer