O – OSCAR
oath of allegiance (to the colors)
obey orders
objective
objective area (OA)
objective rally(ing) point (ORP)
oblique aerial photography
oblique photograph
obscurant
obscurant agent (vision-restricting agent)
obscuration
obscuring smoke
observation aircraft (O; obsn acft)
observation facilities
observation flight
observation helicopter
observation mission
observation patrol
observation point / post (OP)
observation satellite
observation slit
observe
observe a truce
observe, orient, decide, act (OODA)
observed fire
observed fire procedure
observer
observer mission
observer-target line (OT line)
obsolete a weapon
obstacle belt/ course
obstacle development
obstacle pit
obstacle race
obstacle(s)
obstruction
obtain contact
obtain intelligence
obtain surprise
obtaining information
occupation
occupation of position
occupy
ocean convoy
ocean-going tug (boat)
ocean manifest (loading plan)
octogene
off-board sensors
off duty
off-gauge cargo; out-/ oversized cargo
off-grid
off-loading
off-road mine
off-site reconditioning
off target
off-target strike
off-trail movement
offense (брит. offence)
offensive
offensive action
offensive capability
offensive combat
offensive counter-air (ОСА)
offensive countermeasures
offensive electronic warfare
offensive electronic warfare operation
offensive grenade
offensive information operations
offensive operation
offensive patrol
offensive plan
offensive power
offensive reconnaissance
offensive surveillance
offensive weapon(s)
office of civil and defense mobilization
Office of Homeland Security (OHS)
Office of NATO Standardization
Office of NATO Terminology Coordination
Office of Naval Intelligence (ONI)
office of naval research
Office of the Assistant Chief of Staff for Installation Management (OACSIM)
office of the chief of special warfare
Office of the Secretary of Defense (OSD)
Office of the Secretary of the Navy
Office of the Special Envoy of the Secretary-General for the future status process for Kosovo (UNOSEK)
Office of the Special Representative of the Secretary-General for West Africa (UNOWA)
Office of the United Nations Special Coordinator in the Occupied Territories (UNSCO)
Office of U.S. Foreign Disaster Assistance (OFDA)
officer-cadet
officer candidate school
officer commanding (ОС)
officer commissioned from the ranks
officer conducting the exercise (OCE)
officer corps
officer enlistment
officer in charge
officer in charge of logistics
officer in command
officer leadership training course
officer of primary responsibility
officer of the day
officer of the deck
officer of the guard
officer of the line
officer of the watch
officer (offr)
officer Personnel Directorate
officer promotion system
officer rank
officer scheduling the exercise
officer student
officers and men
officers' mess
officer's orderly
officers’ staterooms
official document
official record
official Secrets Act
official travel
offset
offshore
offshore bombardment
offshore operation / surveillance
offshore patrol
offtarget damage
ogive
Ohio-class submarine
oil
oil carrier
oil filter
oil-level gage
oil pan
oil pump
oil slick
oil storage barge (YOS)
oil strainer
oil sump
oil system
oil tank
oil tanker
oil well
oiler (AO)
oleoresin capsicum (OC)
olfactory deception
olive drab
on-board ammunition supply
on-board radar sight
on-board sensor
on-board spares
on-call fire
on-call fires tab
on-call mission
on-call target
on contact
on duty
on guard
on order
on-order mission
on-scene commander
on-site command
on-site commander
on-site directing staff
on-site operations coordination centre
on-site repair
on target
on the alert
on the high seas
on-the-job training
on the strength
one day’s supply
one-man turret
one-piece
one-piece base
one-shot weapon
one-star general
one-time report
one-time report (on status of equipment etc.)
one-up
onslaught
open arrest
open attack
open barrel sight
open boat
open burning and open detonation (OBOD) (= open-pit)
open column
open country/ground/terrain
open emplacement
open fire
open flank
open formation
open hostilities
open order
open out
open position
open range
open route
Open Skies Treaty
open-source information
open source intelligence (OSINT)
open submarine warfare
open time
open weapon emplacement
open wire
open work
open wound
opening
operate
operating environment (OE)
operating forces
operating forces of the Navy
operating frequency
operating mechanism
operating principle
operating procedures
operating range
operating rod assembly
operating rod group
operating speed
operating stocks; working stock
operating tempo (OPTEMPO)
operation and maintenance, Army (OMA)
Operation Enduring Freedom
operation map
operation (Op, OP)
operation order (OPORD)
operation overlay
operation overlay annex
operation plan (OPLAN)
operational
operational activities
operational agency
operational aircraft
operational altitude
operational analysis (OA)
operational and tactical calculations
operational Army
operational art
operational assets
operational attrition
Operational Capabilities Concept (OCC)
operational capability
operational career
operational ceiling (service ceiling)
operational chain of command
operational characteristics
operational command and control
operational command (OPCOM)
operational commander
operational concept
operational contingency support
operational control authority
operational control center
operational control (OPCON)
operational cover
operational decontamination
operational deployment
operational development force
operational documents
operational effectiveness
operational efficiency
operational environment (OE) (obsolete, see `operating environment`)
operational evaluation
operational fatigue
operational flexibility
operational flight/ flying
operational formation
operational framework
operational frequency
operational game
Operational Group of Russian Forces in Transnistria (the)
operational headquarters
operational height
operational intelligence (OPINTEL)
operational-level defense
operational level of war
operational life
operational logistic support
operational logistics
operational loss
operational methods
operational missile
operational mission
operational mobility
operational order
operational order of battle
operational Partnership for Peace
operational pause
operational plan; operation plan
operational planning
Operational Planning Process (OPP)
operational potential
operational priority
operational procedure
operational readiness
operational readiness training
operational rear
operational reconnaissance
operational refuelling of forces
operational report
operational requirement (OR)
operational schedule
operational security (OPSEC)
operational security (OPSEC) measures
operational situation
operational situation report
operational success
operational summary (OPSUM)
operational support
operational task
operational teamwork
operational training
operational training unit
operational trials
operational zone
operationally deployed nuclear forces
operations and maintenance (O&M)
operations and support (O&S)
operations and training officer
operations and training section (G3)
Operations Centre
Operations Directorate
operations division
operations estimate
operations-intelligence net
operations map
operations officer (S3)
operations officer's estimate
operations plan / planning
operations planning
operations room
operations section (G3)
operations security (OPSEC)
Operations, Technical and Support Committee (NATO)
operator
operator control unit (OCU)
operator maintenance
operator’s pack
operator's permit
opiates
opium poppy
opium poppy crops
opportunity fire
opportunity patrol
opportunity squadron
opportunity target
opportunity task
opportunity weapon
opposed boarding
opposed stream crossing
opposing forces (OPFOR)
optical decoy
optical device
optical electronic countermeasures
optical flash
optical gas mask
optical homing
optical intelligence
optical mine-hunting
optical munitions
optical range
optical relay
optical sight
optical target-sensor
optical tracking
optically-tracked
optometry
optronic equipment
oral order
orbiting satellite
order
order for airmobile operation
order of battle (ORBAT)
order of diversion (naut.)
order of march
order of the day
order(s) group
order to move
orderly
orderly landing
orderly officer
orderly room
ordnance
ordnance ammunition depot
ordnance ammunition service
ordnance battalion
Ordnance Corps (OrdC)
ordnance depot
ordnance depot (explosive disposal control)
ordnance detector
ordnance factory/plant
ordnance locator
ordnance maintenance
ordnance officer
ordnance rocket
ordnance supply point
ordnance support
ordnance survey
ordnance unit
ordnance weapons
ordnance yard
ordnanceman
organic
organic and attached assets
organic artillery
organic assignment
organic build-up
organic demolitions
organic dye
organic equipment
organic firepower
organic level of supplies
organic mobility
organic reconnaissance assets
organic supply
organic support elements
organic transportation
organic unit
organization
organization and equipment table
organization chart
organization for combat
Organization for Security and Cooperation in Europe (OSCE)
Organization for the Prohibition of Chemical Weapons (OPCW)
Organization of African Unity (OAU)
Organization of Black Sea Economic Cooperation (BSEC)
organization of ground
organization of routes
organization of the ground
organizational decontamination
organizational equipment
organizational flash
organizational maintenance
organizational repair
organizational strength
organizational tool sets and kits
organizational training
organize
organize the objective
organized defense
orient = orientate
orientation
orientation course
orientation flight
orientation (of military planning)
orientation officer
orienting line
orifice
origin
origin of control
origin of fire
origin of the sweep
origin point
origin (transport)
original destination
original equipment manufacturer (OEM)
original signals
originator
orthogonal axes
orthomorphic projection
ortophoto
OSCE Best Practice Guide on National Procedures for Stockpile Management and Security
OSCE CPC – Conflict Prevention Centre
OSCE Document on Stockpiles of Conventional Ammunition
OSCE FSC – Forum for Security Cooperation
OSCE Special Monitoring Mission (SMM) to Ukraine
oscillating mine
OSINT investigators
other Allied forces for NATO
other forces
Our Mriya will never perish!
out
out of action
out of ground effect (OGE)
out of range
out-of-sight flight
out to you
outboard
outboard motor
outbreak of hostilities
outbreak of violence
outcome of a war
outer bottom
outer case
outer garment
outer hull
outer surfaces
outfit
outflank
outfox
outguard
outgun
outlaw a war
outlay index
outlays
outlet hose
outliers
outline plan
outline the main line of defense (of the enemy)
outnumber (outman)
outpost
outpost area
outpost defenses
outpost engagement
outpost line
outpost troops
output
output element of the antenna
output speed
outrange
outrank
outreach activities
Outreach Countries Section
outreach programme
outside assistance
outside the continental United States (OCONUS)
outsized cargo; off-gauge / oversized cargo
outsourcing
outward bulge
over
over-the-horizon forces
over-the-horizon ground-based radar
over-the-horizon range
overall force multiplier
Overall Summary Appraisal of Defense Planning
overboard
overboots
overcast
overcast bombing
overcoat
overflight interdiction
overgarment
overhaul
overhauling
overhead
overhead concealment
overhead cover(ing) / protection
overhead fire
overhead intelligence
overhead liquid dispersal system (OLDS, NATO)
overlapping coverage
overlay
overlay annex
overlay (e.g. air picture)
overlay-type order
overload
overpack
overreaction (PTSD)
overrun
overrun the objective
overseas base
overseas contingency operations (OCO)
overseas housing allowance (OHA)
overshoot
oversized cargo
overstay one's leave
overt
overt operation
overwhelm defences
overwhelming combat power
oxidizer
oxidizer tank
oxyacetylene cutting
oxygasoline cutting
oxygen
oxygen kit