Officer Basic Course 
on-board computer 
Optical Bar Camera 
Optical Bar Code 
On-Band Computer 
Ontario Building Code 
Octal-to-Binary Conversion 
Office Broadband Communication 
Office of the Bureau Chief 
Officer Billet Code 
Officers Basic Course 
On Board Checkout 
Onboard Blackbody Calibrator 
On-Board Controller 
optimum bactericidal concentration 
Optional, But Cool 
Original Broadway Cast 
Originating Basic Call 
Outside Back Cover 
On-Board Checkout 
Other Backward Classes