Military Dictionary – Letter O

Military Dictionary Letter OHere are the DOD Dictionary terms beginning with the letter O and organized alphabetically. Browse terms from the official DOD Dictionary of Military and Associated Terms that start with O and view definitions. Read on for military definitions that begin with O such as obstacle zone,  on-call target, operational readiness, and more.

Military Dictionary A to Z


See also Official DOD Shortened Word Forms.


object-based production — The intelligence communities’ framework for organizing and sharing information, relating data from all sources to known objects (e.g., units, people, locations, or events). Also called OBP.

objective — 1. The clearly defined, decisive, and attainable goal toward which an operation is directed. 2. The specific goal of the action taken which is essential to the commander’s plan. See also target.

objective area — A geographical area, defined by competent authority, within which is located an objective to be captured or reached by the military forces. Also called OA.

observable — In military deception, the detectable result of the combination of an indicator within an adversary’s conduit intended to cause action or inaction by the deception target.

obstacle — Any natural or man-made obstruction designed or employed to disrupt, fix, turn, or block the movement of an opposing force, and to impose additional losses in personnel, time, and equipment on the opposing force.

obstacle belt — A brigade-level command and control measure, normally depicted graphically, to show where within an obstacle zone the ground tactical commander plans to limit friendly  obstacle employment and focus the defense. See also obstacle.

obstacle clearing — The total elimination or neutralization of obstacles.

obstacle restricted areas — A command and control measure used to limit the type or number of obstacles within an area. See also obstacle.

obstacle zone — A division-level command and control measure to designate specific land areas where lower echelons are allowed to employ tactical obstacles. See also obstacle.

oceanography — The study of the sea, embracing and integrating all knowledge pertaining to the sea and its physical boundaries, the chemistry and physics of seawater, and marine biology.

offensive counterair Offensive operations to destroy or neutralize enemy aircraft, missiles, launch platforms, and their supporting structures and systems both before and after launch, and as close to their source as possible. Also called OCA. See also counterair; defensive counterair; operation.

offensive counterair attack operations — Offensive action by any part of the joint force in support of the offensive counterair mission against surface targets which contribute to the enemy’s air and missile capabilities. Also called OCA attack operations. See also counterair; offensive counterair.

offensive counterintelligence operation — A counterintelligence activity conducted to support Department of Defense and national intelligence, operational, and contingency requirements, using a formally-recruited asset or notional persona, to develop information on, and provide information, materials, or equipment to, a foreign intelligence entity to penetrate the foreign intelligence entity or exploit, disrupt, or manipulate the target in order to counter terrorism, espionage, or other clandestine intelligence activities that threaten the security of the Department of Defense or the United States. Also called OFCO.

offensive cyberspace operations — Missions intended to project power in and through cyberspace. Also called OCO. 

offensive space control — Offensive operations conducted for space negation. Also called OSC.

office — An enduring organization that is formed around a specific function within a headquarters to coordinate and manage support requirements.

officer in tactical command — In maritime usage, the senior officer present eligible to assume command, or the officer to whom the senior officer has delegated tactical command. Also called OTC.

officer of the deck — 1. When underway, the officer designated by the commanding officer to be in charge of the ship, including its safe and proper operation. 2. When in port or at anchor, the officer of the deck is designated by the command duty officer, has similar responsibilities, and may be enlisted. Also called OOD.

official information — Information that is owned by, produced for or by, or is subject to the control of the United States Government.

offset costs — Costs for which funds have been appropriated that may not be incurred as a result of a contingency operation. See also contingency operation.

offshore bulk fuel system — The system used for transferring fuel from points offshore to reception facilities on the beach. Also called OBFS. See also amphibious bulk liquid transfer system; offshore petroleum discharge system.

offshore petroleum discharge system — Provides bulk transfer of petroleum directly from an offshore tanker to a beach termination unit located immediately inland from the high watermark. Also called OPDS. See also facility; petroleum, oils, and lubricants; single-anchor leg mooring.

off-the-shelf item — An item that has been developed and produced to military or commercial standards and specifications, is readily available for delivery from an industrial source, and may be procured without change to satisfy a military requirement.

on-call — 1. A term used to signify that a prearranged concentration, air strike, or final protective fire may be called for. 2. Preplanned, identified force or materiel requirements without designated time-phase and destination information.

on-call target Planned target upon which fires or other actions are determined using deliberate targeting and triggered, when detected or located, using dynamic targeting. See also dynamic targeting; on-call; operational area;  planned target; target.

on hand — The quantity of an item that is physically available in a storage location and contained in the accountable property book records of an issuing activity.

on-scene commander — 1. An individual in the immediate vicinity of an isolating event who temporarily assumes command of the incident. 2. The federal officer designated to direct federal crisis and consequence management efforts at the scene of a terrorist or weapons of mass destruction incident. Also called OSC.

on-station time — The time an aircraft can remain on station, which may be determined by endurance or orders.

open ocean — Ocean limit defined as greater than 12 nautical miles from shore. See also contiguous zone.

open-source information — Information that any member of the public could lawfully obtain by request or observation as well as other unclassified information that has limited public distribution or access.

open-source intelligence — Relevant information derived from the systematic collection, processing, and analysis of publicly available information in response to known or anticipated intelligence requirements. Also  called OSINT.  See  also  intelligence.

operating stocks — Fuel required to sustain daily operations and ensure fuel availability to support United States military forces worldwide. Also called OS.

operation — 1. A sequence of tactical actions with a common purpose or unifying theme. 2. A military action or the carrying out of a strategic, operational, tactical, service, training, or administrative military mission.

operational access — The ability to project military force into an operational area with sufficient freedom of action to accomplish the mission.

operational approach — A broad description of the mission, operational concepts, tasks, and actions required to accomplish the mission.

operational area — An overarching term encompassing more descriptive terms (such as area of responsibility and joint operations area) for geographic areas in which military operations are conducted. Also called OA. See also amphibious objective area; area of operations; area of responsibility; joint operations area; joint special operations area; theater of operations; theater of war.

operational art — The cognitive approach by commanders and staffs—supported by their skill, knowledge, experience, creativity, and judgment—to develop strategies, campaigns, and operations to organize and employ military forces by integrating ends, ways, and means.

operational characteristics — Those military characteristics that pertain primarily to the functions to be performed by equipment, either alone or in conjunction with other equipment; e.g., for electronic equipment, operational characteristics include such items as frequency coverage, channeling, type of modulation, and character  of emission.

operational contract support — The process of planning for and obtaining supplies, services, and construction from commercial sources in support of joint operations. Also called OCS.

operational contract support integration cell — A cell established to coordinate, and integrate operational contract support actions across all primary and special staffs for an operational area. Also called OCSIC.

operational control The authority to perform those functions of command over subordinate forces involving organizing and employing commands and forces, assigning tasks, designating objectives, and giving authoritative direction necessary to accomplish the mission. Also called OPCON. See also combatant command; combatant command (command authority); tactical control.

operational control authority — The naval commander responsible within a specified geographical area for the naval control of all merchant shipping under Allied naval control. Also called OCA.

operational decontamination Decontamination carried out by an individual and/or a unit, restricted to specific parts of operationally essential equipment, materiel, and/or working areas, to minimize contact and transfer hazards and to sustain operations. See also decontamination; immediate decontamination; thorough decontamination.

operational design The conception and construction of the framework that underpins a campaign or operation plan or order. See also campaign; major operation.

operational energy — The energy required for training, moving, and sustaining military forces and weapons platforms for military operations.

operational environment — A composite of the conditions, circumstances, and influences that affect the employment of capabilities and bear on the decisions of the commander. Also called OE.

operational exposure guidance — The maximum amount of nuclear/external ionizing radiation that the commander considers a unit may be permitted to receive while performing a particular mission or missions. Also called OEG. See also radiation exposure status.

operational intelligence — Intelligence that is required for planning and conducting campaigns and major operations to accomplish strategic objectives within theaters or operational areas. See also intelligence; strategic intelligence; tactical intelligence.

operational level of warfare — The level of warfare at which campaigns and major operations are planned, conducted, and sustained to achieve strategic objectives within theaters or other operational areas. See also strategic level of warfare; tactical level of warfare.

operational necessity — A mission associated with war or peacetime operations in which the consequences of an action justify the risk of loss of aircraft and crew. See also mission.

operational pause — A temporary halt in operations.

operational preparation of the environment — The conduct of activities in likely or potential areas of operations to prepare and shape the operational environment. Also called OPE.

operational reach — The distance and duration across which a force can successfully employ military capabilities.

operational readiness — The capability of a unit/formation, ship, weapon system, or equipment to perform the missions or functions for which it is organized or designed. Also called OR.

operational support airlift — Airlift movements of high-priority passengers and cargo with time, place, or mission-sensitive requirements. Also called OSA.

operation and maintenance — Maintenance and repair of real property, operation of utilities, and provision of other services such as refuse collection and disposal, entomology, snow removal, and ice alleviation. Also called O&M.

operation assessment — 1. A continuous process that measures the overall effectiveness of employing capabilities during military operations in achieving stated objectives. 2. Determination of the progress toward accomplishing a task, creating a condition, or achieving an objective.

operation order — A directive issued by a commander to subordinate commanders for the purpose of effecting the coordinated execution of an operation. Also called OPORD.

operation plan — A complete and detailed plan containing a full description of the concept of operations, all annexes applicable to the plan, and a time-phased force and deployment list. Also called OPLAN. See also operation order.

operations center — The facility or location on an installation, base, or facility used by the commander to command, control, and coordinate all operational activities. Also called OC. See also base defense operations center.

operations research The analytical study of military problems undertaken to provide responsible commanders and staff agencies with a scientific basis for decision on action to improve military operations. Also called operational research; operations analysis.

operations security — A capability that identifies and controls critical information, indicators of friendly force actions attendant to military operations, and incorporates countermeasures to reduce the risk of an adversary exploiting vulnerabilities. Also called OPSEC. See also operations security indicators; operations security measures; operations security planning guidance; operations security vulnerability.

operations security assessment — An evaluative process to determine the likelihood that critical information can be protected from the adversary’s intelligence.

operations security countermeasures Methods and means to gain and maintain essential secrecy about critical information.

operations security indicators — Friendly detectable actions and open-source information that can be interpreted or pieced together by an adversary to derive critical information.

operations security planning guidance — Guidance that defines the critical information requiring protection from the adversary and outlines provisional measures to ensure secrecy.

operations security survey — A collection effort by a team of subject matter experts to reproduce the intelligence image projected by a specific operation or function simulating hostile intelligence processes.

operations security vulnerability — A condition in which friendly actions provide operations security indicators that may be obtained and accurately evaluated by an adversary in time to provide a basis for effective adversary decision making.

operations support element — An element that conducts all administrative, operations support, and services support functions within the counterintelligence and human intelligence staff element of an intelligence directorate. Also called OSE.

ordered departure — 1. A procedure by which the number of United States Government personnel, their dependents, or both are reduced at a foreign service post. 2. Mandatory departure of some or all categories of personnel and dependents to designated safe havens as directed by the Department of State, with the implementation of the theater evacuation plan.

order of battle — The identification, strength, command structure, and disposition of the personnel, units, and equipment  of  any  military  force.  Also  called  OB;  OOB.

ordnance — Explosives, chemicals, pyrotechnics, and similar stores, e.g., bombs, guns and ammunition, flares, smoke, or napalm.

ordnance handling — Applies to those individuals who engage in the breakout, lifting, or repositioning of ordnance or explosive devices in order to facilitate storage or stowage, assembly or disassembly, loading or downloading, or transporting.

organic — Assigned to and forming an essential part of a military organization as listed in its table of organization for the Army, Air Force, and Marine Corps, and are assigned to the operating forces for the Navy.

organization for combat — In amphibious operations, task organization of landing force units for combat, involving combinations of command, ground and aviation combat, combat support, and combat service support units, for accomplishment of missions ashore. See also amphibious operation; task organization.

organization for embarkation — In amphibious operations, an organization consisting of temporary landing force task organizations established by the commander, landing force, and a temporary organization of Navy forces established by the commander, amphibious task force, for the purpose of simplifying planning and facilitating the execution of embarkation. See also amphibious operation; embarkation; landing force; task organization.

organization for landing — In amphibious operations, the specific tactical grouping of the landing force for the assault.

Organized Crime and Drug Enforcement Task Force — The network of regional task forces that coordinates federal law enforcement efforts to combat the national and international organizations that cultivate, process, and distribute illicit drugs. Also called OCDETF.

originating medical treatment facility — A medical facility that initially transfers a patient to another medical facility.

originator — The command by whose authority a message is sent, which includes the responsibility for the functions of the drafter and the releasing officer.

oscillating mine — A hydrostatically controlled mine that maintains a pre-set depth below the surface of the water independent of the rise and fall of the tide. See also mine.

outer transport area — In amphibious operations, an area inside the antisubmarine screen to which assault transports proceed initially after arrival in the objective area. See also inner transport area; transport area.

outsized cargo — A single item that exceeds 1,000 inches long by 117 inches wide by 105 inches high in any one dimension. See also oversized cargo.

overhead persistent infrared — 1. Those systems originally developed to detect and track foreign intercontinental ballistic missile systems. 2. Within geospatial intelligence, a capability that provides on-demand, persistent, global, and/or localized coverage of high- to low-intensity infrared events to detect energy radiation from various tactical to strategic objects. Also called OPIR.

overpressure — The pressure resulting from the blast wave of an explosion referred to as “positive” when it exceeds atmospheric pressure and “negative” during the passage of the wave when resulting pressures are less than atmospheric pressure.

Overseas Environmental Baseline Guidance Document A set of objective criteria and management practices developed by the Department of Defense to protect human health and the environment. Also called OEBGD.

oversized cargo — 1. Large items of specific equipment such as a barge; side loadable warping tug; causeway section, powered; or causeway section, nonpowered that require transport by sea. 2. Air cargo exceeding the usable dimension of a 463L pallet loaded to the design height of 96 inches but equal to or less than 1,000 inches in length, 117 inches in width, and 105 inches in height. See also outsized cargo.

over-the-horizon amphibious operation An operation launched from beyond visual and radar range of the shoreline.

overt — Activities that are openly acknowledged by, or are readily attributable to, the United States Government, including those designated to acquire information through legal and open means without concealment through the use of observation, elicitation, or from knowledgeable human sources.

overt  operation  —  An  operation  conducted  openly,   without  concealment.    See also clandestine operation; covert operation.

Military Dictionary A to Z


See also Official DOD Shortened Word Forms.

Source: Official DOD Dictionary of Military and Associated Terms.