Abbreviations Used in Military Documents and for Medal Inscriptions - Abbreviations: O


O Operations Branch of the General Staff, Observer, Officer
O & R RLWY VOL RIF Oudh & Rohilkund Railway Volunteer Rifles
O BDR Lance Bombardier
O DEPT EA Ordnance Department Egyptian Army
O KPL Lance Corporal
O TEL Ordinary Telegraphist
O, OFFR(S) Officer(s)
O/ Ordinary
O/C, OC Officer Commanding
O/Cdt Officer Cadet
O/S Ordinary Seaman, Overseas
O/S, OS Overseas
O/SBCDC Intermediate Overseas Base, Canadian Dental Corps OR Canadian Disciplinary Centre
O/SDCCODRCOC Overseas Detachment Canadian Camp Ordnance Depot, Royal Canadian Ordnance Corps
O/SERS Lance Sergeant
OA,1c(or 2c,3c,4c,5c) Ordnance Artificer, 1st Class (or 2nd,3rd,4th or 5th Class)
OAC Ontario Agricultural College, Ordnance Ammunition Company, Ottawa Area Command
OACRCOC Ordnance Ammunition Company, Royal Canadian Ordnance Corps
OACRO Ottawa Area Command Routine Orders
OAMCU Overseas Air Movements Control Unit
OAP Observation Amphibian Plane (US)
OARCE Officer Administering, Royal Canadian Engineers
OAS On Active Service, Organization of American States
OB Operational Base
OBE Officer of the Order of the British Empire
OBLI, O & BLI Oxfordshire & Buckinghamshire Light Infantry
OBS Obsolete
OBU Operational Base Unit
OBV Ocean Boarding Vessel
OC Officer Commanding, Officer Cadet, Officer of the Order of Canada, Officer's Clerk
OC MED Officer Commanding Medical
OC SURG Officer Commanding Surgeon
OCDP Officer Career Development Plan
OCdr Ordinary Coder
OComm Orders Committee
OCRCRCAMC Oakville Casualty Retraining Centre, Royal Canadian army Medical Corps
OCRN Officer Commanding, Royal Navy
OCS Officer Candidate School, Officers' Chief Steward
OCT Officer Cadet in Training
OCTP Officer Cadet (or Candidate) Training Plan
OCTU Officer Cadet Training Unit
OCU Operational Conversion Unit
OCW Officer-in-Charge Works
OD Air Mechanic (Ordnance)
ODC Ordnance Depot Company
ODSRCOC Ordnance Depot Saskatoon, Royal Canadian Ordnance Corps
ODT Office of Defence Transportation
OEO Ordnance Engineer Office
Off Office
OFF CK Officers Cook
OFF ST , OS Officers Steward
OffcCdt Officer Cadet
OFFICE SUPDT Office Superintendent
Offr, O Officer
OG Operational Group
OGp Orders Group
OGS Officer General Specification
OHA Osmali Horse Artillery, Osmanli Horse Artillery
OHF Occupational History Form
OHMS On His (Her) Majesty's Service
OHQ Overseas Headquarters
Oi/c, OIC Officer of Charge or Command)
OIC Osmali Irregular Cavalry, Osmanli Irregular Cavalry
OILER & GR Oiler & Greaser
OINC Officer-in-Charge, Order in Council
OItoCSGHQEA (Ordnance) Increment to Canadian Section General Headquarters Echelon Army Group
OKH Oberkommando des Heeres (Army High Command, Berlin)
OKW Oberkommando der Wehrmacht (Armed Forces High Command)
OM Order of Merit, Overseas Minister
OMD Ordnance Medical Department
OMERU Ordnance Mechanical Engineers Reinforcement Unit
OMFC Overseas Military Forces of Canada
OMHRCAMC Orillia (or Ottawa, Ozada) Military Hospital, Royal Canadian Army Medical Corps
OMM Officer of the Order of Military Merit
OMO Ordnance Mechanical Officer
ON United Kingdom-North America Convoy, Official Number
ONBASHI Corporal
ONS United Kingdom-North America Slow Convoy
Ont Ontario
ONT MILY HOSP Ontario Military Hospital
ONT RGT, ONTR, OR Ontario Regiment
ONUC Organisation des Nations Unies au Congo
OO Ordnance Officer, Orderly Officer, Operation(al) Order
OOD, OD Officer of the Day
OofPCTintheFAAI Office of the Paymaster Canadian Troops in the Field Allied Armies in Italy
OoftheI-G Office of the Inspector-General
OoftheJAG Office of the Judge Advocate General
OOG Officer of the Guard
OOKEIP VOLS Ookeip Volunteers
OOP Officer of Patrol
OOPE Officer in charge Office Practice & Equipment (Naval)
OOTW Operations Other Than War
OOW Officer of the Watch
OP Observation post, opposite prompt, Operation, Operating
OPA Oxford Patriotic Association
OPD Other Protestant Denomination
OPDP Officer Professional Development Program
OpEEqpt Operator Engineering Equipment
OPI Office of Primary Interest
OPME Officer Professional Military Education
OpMME Operator Mechanic Mobile Equipment
OPO, OO Operation(al) Order
OpRmA Operating Room Assistant
Oprs Director of Military Operations & Intelligence
ops, op operations
OpSbd Operator Switchboard
OpsO Operations Officer
OpSSE Operator (Special Engineering Equipment)
OPtlmn Ordinary Patrolman
OPTR Operator
OPV Offshore Patrol Vessel
OQ Occupation Qualification
OR Ontario Regiment, Other Rank(s), Oxford Rifles, Operating Room Assistant, Orderly, Orderly Room
OR SCTS Orange River Scouts
OR(S) Orderly Rooms, Other Ranks
ORBAT, OOB Order of Battle
ORBS Overseas Recorded Broadcasting Service
ORC PROV MP Orange River Colony Provisional Mounted Police
ORC VOLS Orange River Colony Volunteers
ORD Ordinary Seaman, Ordnance
ORD CLK Orderly Clerk
ORDNANCE DEPT Ordnance Department
Org Director of Organization
ORGN Organization
ORP Polish Ship
ORPEN'S LH Orpen's Light Horse
ORS Ottawa Routing Summary
ORS, OR SGT, OR SJT, ORSE Orderly Room Sergeant
OS Officers School
OS Overseas, Ordinary Seaman, Officer's Steward, Observation Section (Records)
OSAB Officer's Selection Appraisal Board (O-1 Officers' Training Centre)
OSAC Officer Selection Appraisal Centre
OSAIRCOC Ordnance Stores Accounting Inspectorate, Royal Canadian Ordnance Corps
OSC Ordnance Staff Corps, Ordnance Store Company
OSCRCOC Ordnance Store Company, Royal Canadian Ordnance Corps
OSDEF Orkneys & Shetland Defences
OSig Ordinary Signalman
OSMSCMHQRCOC Ordnance Services Mobilization Staff, Canadian Military Headquarters, Royal Canadian Ordnance Corps
OSQ Occupation Specialty Qualification
OSRD Office of Scientific Research and Development
OSS Office of Strategic Services
OSSDRCOC Officers Shop Supply Depot, Royal Canadian Ordnance Corps
OT Occupation Transfer, Aruba-Dakar Convoy
OTC Officers Training Centre (or Corps, Candidate)
OTC"R" Officers Training Centre "Reserve"
OTel Ordinary Telegraphist
OTRM RFLS Outrams Rifles
OTS Officers Training School, Operational Training Squadron
OTU Operational Training Unit(s)
OU Official Use
OUDTSHOORN VR Oudtshoorn Volunteer Rifles
OUT Operational Training Unit
OUTRN RFLS Outranis Rifles
OW/SCoyRCOC Ottawa Workshop Company, Royal Canadian Ordnance Corps
OW/SRCEME Ottawa Workshop, Royal Canadian Electrical and Mechanical Engineers
OW/SRCOC Ordnance Workshop, Royal Canadian Ordnance Corps
OX DVR Ox Driver
OX TPT DEPOT Ox Transport Depot
OXF & BUCKS LI, OX&BUCKSLI Oxfordshire & Buckinghamshire Light Infantry
OXF YEO, OY Oxfordshire Yeomanry
OXV Outer Examination Vessel