Abbreviations starting with O (page 1 of 2)

321 abbreviations begin with O. This page lists O to OTIF.

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0–9

O – Oxygen
O-1 – Officer pay grade 1
O-10 – Officer pay grade 10
O-1E – Officer pay grade 1 with prior enlisted service
O-2 – Officer pay grade 2
O-3 – Officer pay grade 3
O-4 – Officer pay grade 4
O-5 – Officer pay grade 5
O-6 – Officer pay grade 6
O-7 – Officer pay grade 7
O-8 – Officer pay grade 8
O-9 – Officer pay grade 9
O&M – Operations and maintenance
O&P – Ova and parasites
O/E – On examination
O/U – Over/under
O3 – Ozone
OA – Osteoarthritis +2 more
OAA – Outs above average
OAB – Overactive bladder
OAC – Oral anticoagulant +1 more
OAE – Otoacoustic emissions
OAK – Oakland International Airport
OAS – Old Age Security +2 more
OASDI – Old-Age, Survivors, and Disability Insurance
OASIS – Outcome and Assessment Information Set
OAT – Optometry Admission Test +1 more
OAU – Organisation of African Unity
OAuth – Open Authorization
OB – Obstetrics +2 more
OB/GYN – Obstetrics and gynecology
Obad. – Obadiah
ÖBB – Österreichische Bundesbahnen (Austrian Federal Railways)
OBBBA – One Big Beautiful Bill Act
OBD – On-board diagnostics
OBD-II – On-board diagnostics II
OBE – Officer of the Order of the British Empire
OBJ – Wavefront object file +1 more
OBL – Original bill of lading
OBM – Of blessed memory
OBO – Or best offer
OBP – On-base percentage
OBR – Office for Budget Responsibility
Obs – Observation status +3 more
OBX – Outer Banks
OC – Orange County, California +7 more
OCA – Orthodox Church in America
O.Carm. – Order of the Brothers of the Blessed Virgin Mary of Mount…
OCB – Oligoclonal bands
OCC – Office of the Comptroller of the Currency
occas. – Occasionally
OCD – Obsessive-compulsive disorder +2 more
OCdt – Officer Cadet
OCEAN – Openness, conscientiousness, extraversion, agreeableness…
OCF – Operating cash flow
OCGT – Open-cycle gas turbine
OCHA – United Nations Office for the Coordination of Humanitarian…
OCI – Other comprehensive income +3 more
OCIA – Order of Christian Initiation of Adults
OCIE – Organizational clothing and individual equipment
OCIP – Owner-controlled insurance program
OCN – Oncology Certified Nurse
OCONUS – Outside the continental United States
OCP – Oral contraceptive pill +2 more
OCPD – Obsessive-compulsive personality disorder
OCR – Office for Civil Rights +1 more
OCS – Officer Candidate School +1 more
OCSO – Order of Cistercians of the Strict Observance
OCT – October +1 more
OD – Overdose +7 more
ODA – Official development assistance +1 more
ODBC – Open Database Connectivity
ODC – Office of Disciplinary Counsel
ODD – Oppositional defiant disorder +2 more
ODE – Ordinary differential equation
ODF – OpenDocument Format
ODI – One Day International +1 more
ODM – Original design manufacturer
ODNI – Office of the Director of National Intelligence
ODP – OpenDocument Presentation +2 more
ODR – Online dispute resolution
ODS – Ozone-depleting substance +2 more
ODT – Orally disintegrating tablet +1 more
OE – Otitis externa +2 more
OECD – Organisation for Economic Co-operation and Development
OED – Oxford English Dictionary
OEE – Overall equipment effectiveness
OEF – Operation Enduring Freedom
OEM – Original equipment manufacturer
OEP – Open enrollment period +1 more
OER – Open educational resources +1 more
OET – Occupational English Test
OF – Old French
OF-1 – NATO officer grade 1
OF-10 – NATO officer grade 10
OF-2 – NATO officer grade 2
OF-3 – NATO officer grade 3
OF-4 – NATO officer grade 4
OF-5 – NATO officer grade 5
OF-6 – NATO officer grade 6
OF-7 – NATO officer grade 7
OF-8 – NATO officer grade 8
OF-9 – NATO officer grade 9
OFAC – Office of Foreign Assets Control
OFC – Of course +5 more
Ofcom – Office of Communications
OFDM – Orthogonal frequency-division multiplexing
Ofgem – Office of Gas and Electricity Markets
OFM – Order of Friars Minor
OFM Cap. – Order of Friars Minor Capuchin
OFM Conv. – Order of Friars Minor Conventual
Ofqual – Office of Qualifications and Examinations Regulation
OFS – Secular Franciscan Order
Ofsted – Office for Standards in Education, Children's Services and…
Ofwat – Water Services Regulation Authority
OG – Original gangster +5 more
OGC – Office of General Counsel
OGD – Oesophagogastroduodenoscopy
OGG – Kahului Airport +1 more
OGN – Original graphic novel
OGSM – Objectives, goals, strategies and measures
OGT – Orogastric tube
OGTT – Oral glucose tolerance test
OH – Ohio +2 more
OHA – Oral hypoglycemic agent +1 more
OHCA – Out-of-hospital cardiac arrest
OHCHR – Office of the United Nations High Commissioner for Human…
OHG – Offene Handelsgesellschaft (general commercial partnership)
OHI – Other health impairment
OHKO – One-hit knockout
OHP – Overhead press
OHRP – Office for Human Research Protections
OHS – Obesity hypoventilation syndrome
OHSS – Ovarian hyperstimulation syndrome
OHV – Off-highway vehicle +1 more
OI – Opportunistic infection +2 more
OIC – Officer in charge +4 more
OIDC – OpenID Connect
OIF – Operation Iraqi Freedom
OIG – Office of Inspector General
OIH – Opioid-induced hyperalgesia
oint – Ointment
OIR – Operation Inherent Resolve
OIS – Optical image stabilization +2 more
OIT – Oral immunotherapy
OJ – Orange juice
OK – Oklahoma +1 more
OKC – Oklahoma City +2 more
Okla. – Oklahoma
OKR – Objectives and key results
OL – Offensive line
OLAP – Online analytical processing
OLB – Outside linebacker
OLC – Office of Legal Counsel +1 more
OLDCARTS – Onset, Location, Duration, Character, Aggravating factors…
OLE – Object Linking and Embedding
OLED – Organic light-emitting diode
OLS – Ordinary least squares
OLSAT – Otis-Lennon School Ability Test
OLT – Orthotopic liver transplantation
OLTP – Online transaction processing
OM – Otitis media +3 more
OMA – Eppley Airfield
OMB – Office of Management and Budget
OMC – Original male character
OMDB – Over my dead body
OME – Otitis media with effusion
OMFG – Oh my f***ing God
OMFS – Oral and maxillofacial surgery
OMG – Oh my God
OMI – Missionary Oblates of Mary Immaculate
OML – Oh my Lord
OMNY – One Metro New York
OMR – Optical mark recognition +1 more
OMS – Order management system
OMW – On my way
ON – Ontario +1 more
Onc – Oncology
OND – Operation New Dawn
ONDCP – Office of National Drug Control Policy
ONG – On God
ONNX – Open Neural Network Exchange
ONO – Or nearest offer
ONS – Office for National Statistics
Ont. – Ontario +2 more
OOAK – One of a kind
OOB – Out of bed +1 more
OOBE – Out-of-box experience
OOC – Out of character +1 more
OOD – Officer of the deck +1 more
OOF – Out of facility
OOG – Out of gauge
OOH – Out-of-home advertising
OOM – Out of memory +1 more
OOMF – One of my followers
OON – Out-of-network
OOO – Out of office +1 more
OOP – Out-of-pocket +2 more
OOS – Out of stock +1 more
OOTD – Outfit of the day
OOTN – Outfit of the night
OOW – Officer of the watch
OP – Original poster +6 more
op-amp – Operational amplifier
op. cit. – Opere citato (in the work cited)
OPA – Oropharyngeal airway
OPAT – Outpatient parenteral antimicrobial therapy
OPC – One person company
OPCAB – Off-pump coronary artery bypass
OpCo – Operating company
OPCON – Operational control
OPCW – Organisation for the Prohibition of Chemical Weapons
OPD – Outpatient department
OPEC – Organization of the Petroleum Exporting Countries
OPEC+ – OPEC Plus
OpEx – Operating expenditure
OPG – Orthopantomogram
ophth – Ophthalmic
Ophtho – Ophthalmology
OPLAN – Operation plan
OPM – U.S. Office of Personnel Management
OPORD – Operation order
OPOY – Offensive Player of the Year
OPP – Ontario Provincial Police +2 more
Opp'n – Opposition
OPPS – Outpatient Prospective Payment System
OPQRST – Onset, provocation, quality, region/radiation, severity…
O.Praem. – Order of Canons Regular of Prémontré
OPS – On-base plus slugging
OPS+ – Adjusted OPS
OPSEC – Operations security
OPT – Optional Practical Training +1 more
OPTEMPO – Operational tempo
OR – Operating room +3 more
OR-1 – NATO other ranks grade 1
OR-2 – NATO other ranks grade 2
OR-3 – NATO other ranks grade 3
OR-4 – NATO other ranks grade 4
OR-5 – NATO other ranks grade 5
OR-6 – NATO other ranks grade 6
OR-7 – NATO other ranks grade 7
OR-8 – NATO other ranks grade 8
OR-9 – NATO other ranks grade 9
Orch – Orchard
ORCID – Open Researcher and Contributor ID
ORD – O'Hare International Airport
Ore. – Oregon
OREB – Offensive rebounds
Oreg. – Oregon
ORF – Open reading frame
.org – Organization (top-level domain)
ORIF – Open reduction and internal fixation
orig. – Originally
ORLY – Oh, really?
ORM – Object-relational mapping
OROS – Osmotic-controlled release oral delivery system
OROY – Offensive Rookie of the Year
ORR – Objective response rate
ORS – Oral rehydration solution
ORtg – Offensive rating
Ortho – Orthopedics (orthopedic surgery)
ORY – Paris Orly Airport
orz – Kneeling figure (despair or defeat)
OS – Operating system +8 more
OS/2 – Operating System/2
OSA – Obstructive sleep apnea +2 more
OSB – Order of Saint Benedict
OSC – Order to show cause
OSCE – Organization for Security and Co-operation in Europe
OSCP – Offensive Security Certified Professional
OSD – On-screen display +1 more
OSF – Order of Saint Francis
OSFA – One size fits all
OSFED – Other specified feeding or eating disorder
OSG – Office of the Solicitor General
OSH Act – Occupational Safety and Health Act
OSHA – Occupational Safety and Health Administration
OSHA 30 – OSHA 30-Hour Outreach Training
OSI – Open Systems Interconnection (model) +1 more
OSINT – Open-source intelligence
OSL – Oslo Airport, Gardermoen
Osm – Osmolality
OSPF – Open Shortest Path First
OSR – Overseas Service Ribbon
OSS – Open-source software +1 more
OST – Original soundtrack
OSTP – Office of Science and Technology Policy
OSU – Ohio State University +3 more
OSUT – One Station Unit Training
OT – Overtime +6 more
OTA – Over-the-air broadcasting +3 more
OTB – Open to buy
OTC – Over-the-counter
OTD – Doctor of Occupational Therapy +3 more
OTE – On-target earnings
OTel – OpenTelemetry
OTF – OpenType Font
OTG – USB On-The-Go
OTH – Other than honorable
OTIF – On time in full