Ozone Transport Region
Oakland Terminal Railway
Occupational Therapist Registered
Oceanic Transition Route
Oceanic Transition Routes
On the road
Operating Time Record
Optical Tracking
Over-the-Road
Registered Occupational Therapist
Occupational Therapist, Registered
Occupational Therapsit, Registered
ocular tilt reaction
Off The Record
Office of Translational Research
Official Technical Report
Official Test Results
On The Rag
On Time Reporting
oncogenic transformation
one touch recording
Operability test report
Operational Test Readiness
Operational Trouble Report
Operational Turn Round
Operations Training Record
Operations Trouble Report
Operator Trouble Report
Operator Trouble Reports
optical transition radiation