Operator Centralization 
Operations Controller 
Optical Carrier 
Open Confirm 
open circuit 
Office of the Comptroller 
Operating Characteristic 
Office Communication 
Office of Compliance 
Office of Counsel 
Officer Commanding 
Oleoresin Capsicum 
on center 
on condition 
Operating Centers 
Operational Computer 
Operations Center 
operations central 
Operations Coordinator 
Orbital Check 
Organized Crime 
outside circumference 
Oxidation Catalyst 
Oberlin College 
object class 
Observer Controller 
Obsidian Conflict 
Off Campus 
office call 
Office of Communications