FM 101-5-1
Operational Terms and Graphics

Chapter 1


early warning (JP 1-02, NATO) - Early notification of the launch or approach of unknown weapons or weapon carriers. (See also air defense.) See FMs 34-2 and 44-100.

echelon (JP 1-02, NATO) - 1. A subdivision of a headquarters, for example, forward echelon, rear echelon. 2. Separate level of command. As compared to a regiment, a division is a higher echelon; a battalion is a lower echelon. 3. A fraction of a command in the direction of depth to which a principal combat mission is assigned, for example, attack echelon, support echelon, reserve echelon. 4. A formation in which its subdivisions are placed one behind another, with a lateral and even spacing to the same side. (See also airborne operation, command post (CP), and formation.) See FMs 7-7, 7-8, 7-10, 7-20, 7-30, 10-1, 17-95, 71-123, 100-5, 100-10, and 100-15.

echeloned displacement (JP 1-02, NATO) - Movement of a unit from one position to another without discontinuing performance of its primary function. (DOD) Normally, the unit divides into two functional elements (base and advance); and, while the base continues to operate, the advance element displaces to a new site where, after it becomes operational, it is joined by the base element. (Army) - A movement with one element as the base of fire which covers the moving unit's movement to the next position, it is used in both offensive and defensive operations. (See also bound, bounding overwatch, defend, delaying operation, and force projection.) See FMs 6-20 series, 7-7, 7-8, 7-20, 7-30, 17-95, 71-123, 71-100, and 100-15.

echelon formation - A unit formation with subordinate elements arranged on an angle to the left of the direction of attack or to the right (echelon left; echelon right). This formation provides for firepower forward and to the flank of the direction of the echelon. It facilitates control in open areas. It provides minimal security to the opposite flank of the direction of the echeloning. (See also box formation, column formation, diamond formation, formation, line formation, movement formation, vee formation, and wedge formation.) See FMs 7-7, 7-8, and 7-20.

echeloning - The organizing and prioritizing of units for movement. Echelons are often divided into elements such as advance parties, initial combat forces, follow-on forces, and closure forces. See FM 71-100.

echelonment - Organization of elements within a force into three echelons-the assault echelon, the follow-on echelon, and the rear echelon. (See also airborne, assault echelon, follow-on echelon, and rear echelon.) See FMs 7-7, 7-8, 7-10, 7-20, 7-30, 17-95, 71-100, 71-100-2, 71-123, 90-26, and 100-15.

echelons above corps (EAC) (Army) - Army headquarters and organizations that provide the interface between the theater commander (joint or multinational) and the corps for operational matters. See FM 100-5.

economy of force - The allocation of minimum-essential combat capability or strength to secondary efforts so that forces may be concentrated in the area where a decision is sought. Economy of force is a principle of war and a condition of tactical operations. It is not used to describe a mission. (See also main effort.) See FMs 7-30, 17-95, 71-100, 71-123, 100-5, and 100-15.

effective downwind message - A message that forecasts wind speed and direction at heights corresponding to preselected nuclear weapon yields. See FM 3-3.

egress route - The route used to exit enemy territory after the conclusion of a mission such as a deep attack or raid. See FMs 1-111, 7-7, 7-8, 7-10, 7-20, 7-30, 17-95, 71-100, 71-123, 100-15, and 100-103.

electromagnetic deception (JP 1-02) - The deliberate radiation, reradiation, alteration, suppression, absorption, denial, enhancement, or reflection of electromagnetic energy in a manner intended to convey misleading information to an enemy or to enemy electromagnetic-dependent weapons, thereby degrading or neutralizing the enemy's combat capability. Among the types of electromagnetic deception are imitative, manipulative, and simulative. (See also electronic warfare (EW), information warfare (IW), imitative electromagnetic deception (IED), manipulative electromagnetic deception (MED), and simulative electromagnetic deception.) See FMs 34-1 and 34-40.

electromagnetic interference (EMI) (JP 1-02) - Any electromagnetic disturbance that interrupts, obstructs, or otherwise degrades or limits the effective performance of electronics/electrical equipment. It can be induced intentionaloat capability or strength to secondary efforts so that forces may be concentrated in the area where a decisis, intermodulation products, and the like. (See also jamming.) See FM 34-1.

electromagnetic pulse (EMP) (JP 1-02) - The electromagnetic radiation from a nuclear explosion caused by Compton-recoil electrons and photoelectrons from photons scattered in the materials of the nuclear device or in a surrounding medium. The resulting electric and magnetic fields may couple with electrical/electronic systems to produce damaging current and voltage surges. (Army) -- The high-energy, short-duration pulse (similar in some respects to a bolt of lightning) generated by a nuclear or nonnuclear detonation. It can induce a current in any electrical conductor and can temporarily disrupt or overload and damage components of improperly protected or unprotected electronic equipment. See FM 3-3-1.

electromagnetic radiation (JP 1-02) - Radiation made up of oscillating electric and magnetic fields and propagated with the speed of light. Includes gamma radiation; X-rays; ultraviolet, visible, and infrared radiation; and radar and radio waves. See FM 34-40.

electronic attack (EA) (JP 1-02) - That division of electronic warfare involving the use of electromagnetic or directed energy to attack personnel, facilities, or equipment with the intent of degrading, neutralizing, or destroying enemy combat capability. EA includes: 1. actions taken to prevent or reduce an enemy's effective use of the electromagnetic spectrum, such as jamming and electromagnetic deception, and2. employment of weapons that use either electromagnetic or directed energy as their primary destructive mechanism (lasers, radio frequency weapons, particle beams). (See also command and control warfare (C2W) and electronic warfare (EW ).) See FMs 34-1 and 34-40.

electronic protection (EP) (JP 1-02) - That division of electronic warfare involving actions taken to protect personnel, facilities, and equipment from any effects of friendly or enemy employment of electronic warfare that degrade, neutralize, or destroy friendly combat capability. (See also electronic warfare (EW).) See FMs 34-1 and 34-40.

electronics intelligence (ELINT) (JP 1-02) - Technical and geolocation intelligence derived from foreign noncommunications electromagnetic radiations emanating from other than nuclear detonations or radioactive sources. (See also signals intelligence (SIGINT).) See FMs 34-1 and 34-40.

electronic warfare (EW) (JP 1-02) - Any military action involving the use of electromagnetic and directed energy to control the electromagnetic spectrum or to attack the enemy. The three major subdivisions within electronic warfare are: electronic attack, electronic protection, and electronic warfare support. (Army) - The use of electromagnetic energy to determine, exploit, reduce, or prevent hostile use of the electromagnetic spectrum and to ensure friendly use thereof. (See also command and control warfare (C2W) and deception.) See FMs 34-1 and 34-40.

electronic warfare support (ES) (JP 1-02) - That division of electronic warfare involving actions tasked by, or under direct control of, an operational commander to search for, intercept, identify, and locate sources of intentional and unintentional radiated electromagnetic energy for the purpose of immediate threat recognition. Thus, electronic warfare support provides information required for immediate decisions involving electronic warfare operations and other tactical actions such as threat avoidance, targeting, and homing. Electronic warfare support data can be used to produce signals intelligence (SIGINT), communications intelligence (COMINT), and electronics intelligence (ELINT). (See also electronic warfare (EW).) See FMs 34-1 and 34-40.

embarkation (JP 1-02, NATO) - The process of putting personnel and/or vehicles and their associated stores and equipment into ships and/or aircraft. (See also aerial port of embarkation (APOE) and amphibious operation.) See FMs 20-12 and 55-12.

embarkation order (JP 1-02, NATO) - An order specifying dates, times, routes, loading diagrams, and methods of movement to shipside or aircraft for troops and their equipment. (See also movement table and operation order (OPORD).) See FM 101-5.

emergency procedure - A mandatory procedure that a flight crew must perform to preclude loss of life or injury and to avoid damage to the aircraft when an aircraft malfunction occurs. See FMs 1-111, 1-112, 1-116, and 100-103.

emergency resupply (JP 1-02) - A resupply mission that occurs based on a predetermined set of circumstances and time interval should radio contact not be established or, once established, is lost between a special operations tactical element and its base (See also automatic resupply and on-call resupply.)

emergency risk (nuclear) (JP 1-02) - A degree of risk where anticipated effects may cause some temporary shock and casualties and may significantly reduce the unit's combat efficiency. (Army) - Emergency risk is accepted only when absolutely necessary. It includes vulnerability categories expressed in terms of risk to unwarned, exposed personnel; exposed personnel; warned, protected personnel. (See also degree of risk (nuclear) , moderate risk (nuclear), negligible risk (nuclear), and troop safety (nuclear) .) See FM 100-30 and JPs 3-12.2 and 3-12.3.

emplacement (JP 1-02, NATO) - 1. A prepared position for one or more weapons or pieces of equipment for protection against hostile fire or bombardment, and from which soldiers can execute their assigned tasks. 2. The act of fixing a gun in a prepared position from which it may be fired. (See also defend.) See FMs 5-103, 6-20 series, 7-7, 7-8, 7-90, and 71-123.

encirclement - The loss of freedom of maneuver to one force resulting from an enemy force's control of all routes of egress and reinforcement. (See also breakout and linkup.) See FMs 6-20, 7-20, 7-30, 17-95, 71-100, 71-123, and 100-5.

encircling force - In pursuit operations, the force which is to get to the rear of the enemy and block his escape so that he can be destroyed between the direct pressure and encircling force. This force advances or flies along routes paralleling the enemy's line of retreat. This force may also attack into the flank of a retreating enemy. (See also block, envelopment, and pursuit.) See FMs 1-111, 1-112, 7-10, 7-20, 7-30, 17-95, 71-100, 100-5, and 100-15.

end evening civil twilight (EECT) - Occurs when the sun has dropped 6 degrees beneath the western horizon and is the instant at which there is no longer sufficient light to see objects with the unaided eye. Light intensification devices are recommended from this time until begin morning civil twilight (BMCT). (See also limited-visibility operations and twilight.)

end evening nautical twilight (EENT) - Occurs when the sun has dropped 12 degrees beneath the western horizon and is the instant of last available daylight. At the EENT, there is no further sunlight visible. (See limited-visibility operations and twilight.)

end of mission (JP 1-02, NATO) - In artillery and naval gunfire support, an order given to terminate firing on a specific target. (Army) - Pertains to mortar fire also. (See also cease loading, call for fire, and fire mission.) See FMs 6-20 series and 7-90.

end state (Army) - A set of required conditions that, when achieved, attain the aims set for the campaign or operation. (See also commander's intent and operation order (OPORD).) See FM 101-5.

enemy - The individual, group of individuals (organized or not organized), paramilitary or military force, national entity, or national alliance that is in opposition to the United States, its allies, or multinational partners.

enemy prisoner of war (EPW) - Enemy personnel captured during operations conducted in war or combat, or stability and support operations. See FMs 19-40 and 27-10.

enfilading fire - A type of engagement where the beaten zone of the firing weapon is on the long axis of the target being engaged. This usually occurs from the flank of the target. See FMs 7-7, 7-8 and 7-10.

engage (JP 1-02, NATO) - In air defense, a fire control order used to direct or authorize units and/or weapon systems to fire on a designated target. (See also cease fire.)

engagement (JP 1-02) - In air defense, an attack with guns or air-to-air missiles by an interceptor aircraft, or the launch of an air defense missile by air defense artillery and the missile's subsequent travel to intercept. (Army) - A small tactical conflict, usually between opposing maneuver forces. (See also battle and campaign.) See FMs 1-112, 7-7, 7-8, 7-10, 7-20, 7-30, 17-95, 44-100, 71-123, 100-5, and 100-15.

engagement area (EA) - An area along an enemy avenue of approach where the commander intends to contain and destroy an enemy force with the massed fires of all available weapons. The size and shape of the engagement area is determined by the relatively unobstructed intervisibility from the weapon systems in their firing positions and the maximum range of those weapons. Sectors of fire are usually assigned to subordinates to prevent fratricide. (See also defend.) See FMs 1-111, 1-112, 7-10, 7-20, 7-30, 17-95, 71-100, 71-123, 100-5, and 100-15.

engagement criteria - Those circumstances that allow engagement of an enemy force without a specific command to do so. Examples are a point or line on the ground that an enemy crosses or an event or action that an enemy does. (See also engagement area (EA) and decision point (DP).) See FMs 6-series, 7-7, 7-8, 7-10, 7-20, 7-90, 7-91, 17-12, 17-95, 23-1, 71-123, and 101-5.

engagement priorities - The sequence for attack of targets in order of importance assigned to specific weapon systems to facilitate the destruction of threat vehicles expected in an armored formation. Engagement priorities are assigned based on the type or level of threat at different ranges to best match organic weapon system capabilities against threat vulnerabilities. See FM 101-5.

engineer regulating point (ERP) - Checkpoint to ensure that vehicles do not exceed the capacity of the crossing means and to give drivers final instructions on site-specific procedures and information, such as speed and vehicle interval. See FMs 5-71-100, 5-100, and 5-114.

engineer work line - A coordinated boundary or phase line used to compartmentalize an operational area to indicate where specific engineer units have primary responsibility for the engineer effort. It may be used at division level to discriminate between a sector supported by division engineer assets and a sector supported by direct support or general support corps engineer units. See FMs 5-71-100, 5-100, and 5-114.

envelopment (JP 1-02, NATO) - An offensive maneuver in which the main attacking force passes around or over the enemy's principal defensive positions to secure objectives to the enemy's rear. (Army) - It is one of the five choices of maneuver. A commander must find or create an assailable flank by passing forces around one or both of, or over (vertical), the sides of an enemy force, pitting his strength against the enemy's weakness. (See also attack, choices of maneuver, double envelopment, encircling force, offensive operations, and turning movement.) See FMs 1-111, 1-112, 7-20, 7-30, 17-95, 71-100, 71-123, 100-5, and 100-15.

escort (JP 1-02, NATO) - 1. A combatant unit(s) assigned to accompany and protect another force or convoy. 2. Aircraft assigned to protect other aircraft during a mission. 3. An armed guard that accompanies a convoy, a train, prisoners, etc. 4. An armed guard accompanying persons as a mark of honor. (DOD) 5. To convoy. 6. A member of the Armed Forces assigned to accompany, assist, or guide an individual or a group, such as an escort officer. See FMs 1-111, 1-112, 7-30, 17-95, 71-100, 71-123, 100-5, 100-15, and 100-20.

essential elements of friendly information (EEFI) (JP 1-02) - Key questions likely to be asked by adversary officials and intelligence systems about specific friendly intentions, capabilities, and activities so that they can obtain answers critical to their operational effectiveness. (Army) - The critical aspects of a friendly operation that, if known by the enemy, would subsequently compromise, lead to failure, or limit success of the operation, and therefore must be protected from enemy detection. (See also commander's critical information requirements (CCIR).) See FMs 34-1 and 101-5.

essential elements of information (EEI) (JP 1-02) - The critical items of information regarding the enemy and the environment needed by the commander by a particular time to relate with other available information and intelligence in order to assist in reaching a logical decision. (Army) - Within US Army doctrine, priority intelligence requirements equate to EEI. (See also commander's critical information requirements(CCIR).) See FM 101-5.

evacuation (JP 1-02) - 1. The process of moving any person who is wounded, injured, or ill to or between medical treatment facilities. 2. The clearance of personnel, animals, or materiel from a given locality. 3. The controlled process of collecting, classifying, and shipping unserviceable or abandoned material, United States and foreign, to appropriate reclamation, maintenance, technical intelligence, or disposal facilities. (Army) - 1. The ordered or authorized departure of noncombatants from a specific area by the Department of State, Department of Defense, or appropriate military commander. This refers to the movement from one area to another in the same or different countries. The evacuation is caused by unusual or emergency circumstances and applies equally to command or noncommand-sponsored family members. 2.A combat service support function that involves the movement of recovered material, personnel, casualties, bodies, prisoners of war, and so forth, from a forward collection point along a main supply route to a rearward, usually higher unit, exchange point, or facility. (See also collection point and medical evacuation (MEDEVAC).) See FMs 1-111, 1-112, 7-10, 7-20, 7-30, 8-10-6, 17-95, 17-100, 71-123, 100-5, and 100-15.

evacuation force - In noncombatant evacuation operations, the element that conducts in-country evacuation operations, including advance party, evacuation control center, marshalling, and force protection operations. (See also evacuation.) See FM 90-29.

evacuation site - In noncombatant evacuation operations, the location, selected by the embassy and occupied by the evacuation force, where evacuees are consolidated and prepared for evacuation . It is usually located near the point of embarkation. (See also evacuation.) See FM 90-29.

evasion and escape (E&E) (JP 1-02, NATO) - The procedures and operations whereby military personnel and other selected individuals are enabled to emerge from an enemy-held or hostile area to areas under friendly control. See FMs 1-111 and 100-25.

event template - A model against which enemy activity can be recorded and compared. It represents a sequential projection of events that relate to space and time on the battlefield and indicate the enemy's ability to adopt a particular course of action. Event templates are not graphics inscribed on plastic or drawings of force dispositions, but lists of enemy action in chronological sequence, with each enemy action being an indicator of his intent (See also doctrinal template, decision support template (DST), and situational template.) See FMs 34-1, 34-130, and 101-5.

exclusive standoff zone (Army) - A controlled area surrounding a facility in which only service and delivery vehicles are allowed. The perimeter of this area is defined by barriers and is set at a standoff distance sufficient to reduce the blast effects of a vehicle bomb. See FMs 5-114 and 100-20.

execution matrix - A visual and sequential representation of the critical tasks and responsible organizations by phase for a tactical operation used as a staff tool. See FMs 71-123 and 101-5.

exercise (JP 1-02, NATO) - A military maneuver or simulated wartime operation involving planning, preparation, and execution. It is carried out for the purpose of training and evaluation. It may be a combined, joint, or single-Service exercise, depending on participating organizations. (See also command post exercise (CPX) and maneuver.) See FMs 25-100 and 25-101.

exfiltration (JP 1-02) - The removal of personnel or units from areas under enemy control. (Army) - The removal of personnel or units from areas under enemy control by stealth, deception, surprise, or clandestine means. See FMs 1-111, 1-112, 7-7, 7-8, 7-10, 7-20, 7-30, 17-95, 71-100, 71-123, 100-5, and 100-15.

expedient flight route - Flight route that is established with preselected and disseminated checkpoints. For a specific mission, the commander can define an expedient flight route by reference to these checkpoints when limited time is available to develop and disseminate pickup and landing zones and flight route information. See FMs 1-111, 1-112, 1-116, 90-4, and 100-103.

expeditionary force (JP 1-02) - An armed force organized to accomplish a specific objective in a foreign country. (See also combatant command and joint task force (JTF).) See FMs 71-100, 100-5, 100-15, and 100-20.

exploitation (JP 1-02, NATO) - 1. Taking full advantage of success in battle and following up initial gains. 2. Taking full advantage of any information that has come to hand for tactical, operational, or strategic purposes. 3. An offensive operation that usually follows a successful attack and is designed to disorganize the enemy in depth. (See also attack and pursuit.) See FMs 1-111, 1-112, 7-7, 7-8, 7-10, 7-20, 7-30, 17-95, 17-123, 71-100, 100-5, and 100-15.

explosive ordnance disposal (EOD) (JP 1-02, NATO) - The detection, identification, on-site evaluation, rendering safe, recovery, and final disposal of unexploded explosive ordnance. It may also include explosive ordnance which has become hazardous by damage or deterioration. See FM 5-250.

exposure - The frequency and length of time subjected to a hazard.

exposure dose (JP 1-02, NATO) - The exposure dose at a given point is a measurement of radiation in relation to its ability to produce ionization. The unit of measurement of the exposure dose is the roentgen. (See also absorbed dose and dose rate.) See FM 3-3-1.

external load - A person, piece of equipment, or pallet or package of supplies transported by being suspended externally to a helicopter by a lifting service consisting of a combination of a cargo hook or hooks, an external hoist, or a sling apparatus. See FMs 55-450-3/ 4/5.

extraction zone (EZ) (JP 1-02, NATO) - A specified drop zone used for the delivery of equipment and/or supplies by means of an extraction technique from an aircraft flying very close to the ground. (See also air assault, airborne operation, and airhead line.) See FMs 7-30, 71-100-2, and JP 3-18.1.

Updated 27 July 1997.

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