Contract Administration Office 
Chief Administrative Officer 
Compliance Advisor Ombudsman 
Carraro 
Customer Assistance Office 
Computer Aided Office 
Computer-Assisted Ordering 
Corrective Action Order 
Calcium Oxide 
Center Adjudications Officer 
Central Accounting Office 
Chief Acquisition Officer 
Chronic airway obstruction 
Computer-Aided Optimization 
Congressional Activities Office 
Constant Administrative Office 
Coordination of Atomic Operations 
Counter Air Operation 
Crisis Action Organization 
Air China Cargo 
Canadian Association of Optometrists 
Canadian Association of Orthodontists 
Cargo Aircraft Only 
Carlsbad Area Office 
carotid artery occlusion 
Casualty Assistance Office 
Catania Astrophysical Observatory 
Central Action Office 
Central Aerological Observatory 
Central Application Office