Operational Test Command 
Officer in Tactical Command 
Over the Counter 
Ozone Transport Commission 
Operating Telephone Company 
Operating Telefone Company 
Operational Test Center 
Orbiter Test Conductor 
Overhead Trip Computer 
Over-the-Counter 
Officer Training Corps 
Official Test Centre 
Online Training Center 
Ouachita Technical College 
oxytetracycline 
Occupational Training Center 
Ocean Thermal Conversion 
ochratoxin C 
odor threshold concentration 
off the case 
Office for Topography and Cartography 
Office of Technical Coordination 
Office of Technology Commercialization 
Office of Treaty Compliance 
OFFICE TECHNOLOGY CENTER 
Office Technology Coordinator 
Officers' Training Corp 
Officers Training Corps 
Offshore Technology Conference 
offsite training center