A practical reference for the terminology used in UAP/UFO reports, government archives, pilot and radar cases, infrared video, aviation tracking, satellite identification and the UAPLocations Live Sky Scanner. Definitions distinguish technical terms from historical or informal UFO language where that distinction matters.
Search for an abbreviation such as LEO, TLE, ADS-B, FLIR, FOIA or AARO, or browse by category. A label such as unresolved, orb or transmedium describes the status or wording of a report; it is not automatically evidence of an extraordinary origin.
UAPLocations uses these terms to help compare official records with known aircraft, satellites, astronomical objects and sensor effects. Source agencies may use different terminology, so the original linked record remains authoritative for the wording of a specific case.
Core labels used in modern UAP reporting, historical UFO records and case-resolution language.
A modern umbrella term for anomalous observations that cannot initially be identified or readily explained from the available data. UAP does not by itself imply extraterrestrial origin.
An older and still widely used term for an observed object or phenomenon in the sky that has not been identified at the time of reporting.
Aerial-focused wording used before the broader all-domain use of UAP became common in U.S. government reporting.
A detection, measurement or observation that does not match the expected pattern or cannot yet be reconciled with known objects or conditions.
A status meaning the available information is insufficient to determine what the reported object or phenomenon was.
A report for which investigators assign a sufficiently supported explanation or identification based on the available evidence.
A report that remains without a sufficiently supported explanation after review. Unresolved does not mean extraordinary; it can reflect limited or poor-quality data.
A case in which the evidence is too incomplete, ambiguous or low quality to support a reliable identification.
A proposed explanation that fits much of the available evidence but is not strong enough to be treated as definitive.
A provisional explanation that remains subject to confirmation or additional evidence.
A known object or phenomenon that was initially perceived or reported as unidentified.
A sensor or analytical detection that appears to indicate a target or anomaly but is later attributed to noise, processing, clutter or another non-target cause.
The process of comparing a report with sensor data, astronomy, aviation, weather, orbital data and other evidence to determine the most supported explanation.
An ordinary explanation such as an aircraft, balloon, satellite, astronomical object, atmospheric effect or sensor artifact.
Additional evidence from another witness, sensor or data source that supports the same event, location or timing.
An observation or analytical context involving more than one operational domain, such as air, sea, space or transmedium environments.
A descriptive term for an object or phenomenon reported as moving between operational environments, for example air and water. The label describes the report, not a confirmed capability.
An informal UFO/UAP expression for reports containing unusually complex or difficult-to-reconcile features. It is not a standardized scientific or government classification.
An informal set of claimed UAP characteristics popular in public discussion. It should not be treated as an official diagnostic test or proof of extraordinary technology.
The reported visual form or shape of an object, such as sphere, disc, triangle, cylinder or point-like light.
Common report formats, evidence packages and archival document types found in UAP collections.
A report based primarily on what a witness saw directly rather than on an instrument-only detection.
A sighting or sensor report submitted by a pilot or other aircrew member.
A report generated by military flight personnel and often accompanied by operational, radar or sensor context.
A report involving air traffic control personnel, radio communications, radar data or operational records.
A report based on a radar detection, track or correlated sequence of radar returns.
A case based on data from one or more sensors such as radar, infrared, electro-optical or electronic-support systems.
A case in which two or more independent sensors or evidence streams record or support the same event.
A report supported by visible-light and/or infrared imaging sensors.
A report that includes one or more still images as evidence.
A report that includes recorded moving imagery, which may be visible-light, infrared or another imaging modality.
A report that includes recorded sound, radio traffic, cockpit audio or other relevant communications.
A written or recorded account provided by a person who observed or participated in the reported event.
A formal or semi-formal record describing when, where and how an incident occurred and what was observed or detected.
A collection of documents, media and analysis assembled around one incident or investigation.
A report produced within an intelligence process. Its existence or classification level does not by itself establish the accuracy of every claim it contains.
An internal written communication used to summarize observations, decisions, analysis or administrative actions.
A concise presentation or document prepared to inform officials, analysts or operational personnel.
Communications between individuals, offices or agencies that may document a case, request, referral or analytical discussion.
A descriptive sheet accompanying an archival release or media item, often listing segments, locations, dates or production information.
A written rendering of recorded speech, interview, radio traffic or video dialogue.
A time-ordered operational entry recording events, observations, aircraft activity or other actions.
Time-stamped machine data transmitted or recorded by an aircraft, spacecraft, sensor or other system.
A government response to a records request that may include released documents, redactions, exemptions or a statement that responsive records were not found.
A record whose prior national-security classification has been removed or reduced through an authorized process.
A released record from which some information has been obscured or withheld, usually under legal, privacy or security authorities.
A report submitted by a member of the public. On UAPLocations, community material is kept distinct from official-source records and is not automatically treated as verified.
A second record referring to the same underlying event, media or incident.
An older report studied mainly through surviving records, media, correspondence or later releases rather than live investigation.
Technical terms used in radar, infrared, electro-optical and digital evidence analysis.
Visible-light or near-visible imaging using electronic cameras or optical sensors.
Electromagnetic radiation beyond visible red light; infrared sensors can image heat-related contrast or reflected/emitted infrared energy.
An infrared imaging system commonly mounted on aircraft or vehicles to view thermal contrast in the forward field of regard.
Imaging based on infrared energy associated with temperature differences rather than ordinary visible-light color.
An infrared spectral band often used by military and scientific imaging systems.
An infrared spectral band commonly used for thermal imaging of objects and environments.
A system that transmits radio energy and analyzes returned signals to estimate target range, direction, motion or other properties.
Radar that detects targets from reflected radio energy without requiring the target to transmit a cooperative reply.
A cooperative surveillance system that interrogates aircraft transponders and receives coded replies.
A change in observed frequency caused by relative motion, commonly used by radar to estimate radial velocity.
A measure of how strongly an object reflects radar energy toward a receiver; it is not simply the physical size of the object.
Unwanted radar returns from terrain, sea, weather, birds, buildings or other background sources.
A time-linked set of detections treated by a tracking system as belonging to the same target.
A measure or assessment of how reliably a sensor or fusion system is maintaining a target track.
Combining information from multiple sensors or sources to form a more coherent estimate of a target or event.
Intelligence derived from intercepted or analyzed signals. The term covers multiple technical sub-disciplines.
A SIGINT discipline focused mainly on non-communications electronic emissions such as radar signals.
Systems and techniques used to detect, identify and locate electromagnetic emissions for situational awareness.
A broad term for electromagnetic frequencies used by radar, communications, navigation and many other systems.
A radar imaging technique that uses platform motion and signal processing to create high-resolution images of the ground or targets.
Descriptive or technical information stored with a file or record, such as timestamps, device details, dimensions, codec or location.
Metadata commonly embedded in photographs, potentially including capture time, camera model, exposure settings and GPS coordinates.
A time reference attached to frames, files or sensor data that helps synchronize multiple evidence sources.
A visual distortion introduced by lossy image or video compression rather than by the observed scene.
Spreading or enlargement of a very bright source in an image when a sensor approaches or reaches saturation.
A defective or noisy image-sensor pixel that can appear as a persistent bright point.
Geometric distortion caused when different image rows are captured at slightly different times during rapid motion.
Internal reflections or scattering inside a lens system that can create bright spots, rings or streaks unrelated to an external object.
The appearance of out-of-focus points of light, which can turn stars, aircraft lights or other sources into discs or polygonal shapes.
The process of characterizing and correcting a sensor so its measurements correspond as accurately as possible to known references.
Terms that describe where an object appears, how a camera is oriented and how apparent motion should be interpreted.
Horizontal direction measured around the horizon, usually clockwise from north from 0° to 360°.
Angular height above the local horizon. 0° is the horizon, 90° is the zenith and negative values are below the horizon.
The point in the sky directly above the observer, corresponding to 90° elevation.
The point directly below the observer, opposite the zenith.
The apparent boundary between sky and ground/sea; in calculations it is the 0° elevation reference.
The straight viewing direction between an observer or sensor and a target.
The angular extent of the scene visible to a camera, sensor or optical system.
The horizontal direction from the observer toward a target, usually expressed relative to north.
The direction the nose of an aircraft or vehicle points, which can differ from the actual path over the ground.
The direction an object is actually moving across the Earth, which may differ from heading because of wind or other effects.
Rotation around the lateral axis that raises or lowers the nose or viewing direction.
Rotation around the forward axis, such as tilting a phone or banking an aircraft.
Rotation around the vertical axis that turns the nose or viewing direction left or right.
Distance from the observer or sensor to a target. The exact meaning depends on the measurement method.
Straight-line distance from an observer or sensor to a target at a different altitude.
Vertical position above a defined reference such as mean sea level or the local surface.
Altitude measured relative to the ground directly below or near the object.
A common altitude reference based on mean sea level rather than local ground height.
The angle an object spans in the observer’s field of view; it depends on both physical size and distance.
The rate at which an object appears to move across the observer’s field of view, usually expressed in degrees per unit time.
Apparent displacement of an object caused by a change in the observer’s position or viewing geometry.
Changes in apparent size, spacing or motion that result from the geometry between observer, camera and target.
Estimating a target position using directions or measurements from multiple separated observation points.
A defined coordinate system used to express position or orientation, such as Earth-fixed, device, screen or camera coordinates.
An astronomical coordinate analogous to celestial longitude, used with declination to locate objects on the celestial sphere.
An astronomical coordinate analogous to celestial latitude, measured north or south of the celestial equator.
Terms useful for checking whether a reported object may be an aircraft, drone, balloon or air-traffic event.
A cooperative aircraft-surveillance technology in which equipped aircraft broadcast position, altitude, speed, identity and other data derived from onboard navigation systems.
The aircraft function that broadcasts surveillance information to ground stations and other equipped aircraft.
The capability to receive traffic and other supported ADS-B information in the cockpit or on a compatible system.
An aircraft radio device that replies to surveillance interrogations and can transmit identity and altitude information.
A selective aircraft-transponder mode that supports unique aircraft addressing and data exchange.
A transponder mode that includes pressure-altitude information in replies.
A four-digit code assigned or used by an aircraft transponder to help air traffic control identify a flight or situation.
The radio or operational identifier used for an aircraft, flight or unit.
A globally assigned 24-bit aircraft address commonly displayed as a six-character hexadecimal identifier.
The civil registration mark assigned to an aircraft by its national aviation authority.
A pressure-altitude reference expressed in hundreds of feet above the standard pressure datum, for example FL350.
Altitude derived from atmospheric pressure using a standard pressure reference rather than direct GPS height.
An aircraft’s speed relative to the ground.
The rate at which an aircraft or tracked object gains or loses altitude.
Services and personnel responsible for managing aircraft separation and the safe, orderly flow of air traffic.
A time-sensitive aviation notice containing information important to flight operations, such as hazards, closures or temporary changes.
A temporary restriction on aircraft operations in a specified area for safety, security or other authorized reasons.
Airspace in which air traffic control services and operational requirements apply according to the applicable airspace class.
The phase and procedure by which an aircraft descends and aligns for landing.
The phase or published procedure used as an aircraft climbs away from an airport.
A racetrack-shaped flight pattern used to delay or sequence aircraft while remaining in a defined area.
An airborne system that uses transponder information to warn pilots about nearby traffic and potential collision conflicts.
A method of locating aircraft by comparing the arrival times of radio transmissions at multiple ground receivers.
An unmanned aircraft together with the control station, communications links and other components required to operate it.
A small unmanned aircraft system; exact regulatory weight limits vary by jurisdiction.
A common non-technical label for an unmanned aircraft. In regulation and operations, UAS often refers to the complete system rather than only the aircraft.
A system in which many drones broadcast identification and location-related information to support accountability and airspace awareness.
A balloon used to carry instruments into the atmosphere for weather observations.
A sensor package carried by a weather balloon that measures atmospheric variables and transmits data to a receiving station.
A visible ice-cloud trail that can form behind aircraft when hot exhaust mixes with cold, humid air at altitude.
Standard colored aircraft lights used to indicate orientation, typically red on the left wingtip, green on the right and white toward the rear.
A flashing or rotating aircraft light intended to make the aircraft conspicuous and reduce collision risk.
Bright forward-facing aircraft lights used during takeoff, landing and ground operations; at distance they can appear as a stationary bright point.
Terms used by the Live Sky Scanner and orbital catalogs to distinguish satellites, rocket bodies, debris and launches from unexplained observations.
Low Earth orbit, generally the region from roughly 160 km to 2,000 km above Earth. Many imaging satellites, the ISS and much of the Starlink constellation operate in LEO.
The orbital region above LEO and below geosynchronous altitude; many navigation satellites operate in MEO.
A circular equatorial orbit at about 35,786 km altitude where a satellite appears fixed over one longitude.
An orbit with a period matching Earth’s rotation; unlike a geostationary orbit, it need not be circular or equatorial.
An orbit with a large difference between perigee and apogee, producing long dwell times near the high point.
A near-polar orbit designed so the satellite passes locations at approximately the same local solar time.
An orbit with inclination near 90°, allowing a spacecraft to pass over or near the polar regions.
The region of space extending around Earth toward and around the Moon, often used in discussions of operations beyond near-Earth orbit.
A commonly used conventional boundary of space at 100 km above mean sea level.
A legacy two-line format for general-perturbations orbital data used with SGP4 to estimate the position of an Earth-orbiting object.
Orbital element data designed for propagation with simplified general-perturbations models such as SGP4; TLE is one legacy representation.
A CCSDS format for orbital mean elements that avoids some limitations of the legacy TLE format.
A standard orbit-propagation model used with GP/TLE-style mean elements to estimate satellite positions over time.
A catalog identifier assigned to a tracked space object in the U.S. space-object catalog.
An identifier indicating the launch year, launch sequence and piece from that launch, for example 1998-067A for the ISS.
The reference date and time at which a set of orbital elements is defined.
The angle between an orbit plane and Earth’s equatorial plane.
A number describing how circular or elongated an orbit is; zero corresponds to a perfect circle.
The point in an Earth orbit farthest from Earth.
The point in an Earth orbit closest to Earth.
The time required for an object to complete one orbit.
An orbital element describing the orientation of the orbit plane around Earth.
An orbital element locating perigee within the orbital plane.
An orbital element that represents an object’s position within its orbit at the epoch in a mathematically convenient form.
The spacecraft or mission hardware carried to orbit to perform the intended mission.
A launch-vehicle stage or other rocket hardware that remains in orbit after performing its launch function.
Human-made objects or fragments in orbit that no longer serve an operational mission.
A general term for a tracked artificial object in space, including active satellites, rocket bodies and debris.
The return of an orbital object into denser layers of Earth’s atmosphere, often leading to breakup or burn-up.
A gradual reduction of orbital altitude, often driven by atmospheric drag, eventually leading to reentry for low-orbit objects.
The path on Earth’s surface directly beneath a satellite as it moves along its orbit.
A period when an orbiting object is above the observer’s local horizon.
The highest elevation a satellite or astronomical object reaches during a particular pass or transit.
A closely spaced group of recently launched Starlink satellites that can appear as a line of moving lights before the spacecraft spread out.
A temporary brightening caused when sunlight reflects strongly from a satellite or spacecraft surface toward the observer.
A large crewed spacecraft in low Earth orbit that can become one of the brightest moving objects in the night sky during favorable passes.
A time interval during which a launch can occur while meeting mission, orbital, safety and range constraints.
A launch whose payloads and rocket hardware may not yet have mature or widely distributed orbital data.
Common natural or astronomical sources that can be mistaken for unusual aerial phenomena, especially in low-light video.
A self-luminous astronomical object. Bright stars can scintillate strongly near the horizon and appear to change color or move in unstable handheld footage.
A Solar System body that can appear as a very bright, steady point of light; Venus and Jupiter are frequent sources of mistaken sightings.
Often the brightest planet visible from Earth and a common source of reports describing a stationary or slowly changing bright light.
A very bright planet that can be conspicuous for hours and may be misperceived as an unusual light when viewed without a stable reference.
The brightest star in Earth’s night sky; atmospheric turbulence can make it flash strongly in different colors, especially near the horizon.
A brief streak of light produced when a meteoroid heats and ablates while entering Earth’s atmosphere.
A meteor significantly brighter than typical shooting stars.
A term often used for an exceptionally bright meteor, sometimes associated with fragmentation or an atmospheric explosion.
A period when many meteors appear to radiate from a common region of the sky because Earth is passing through a stream of debris.
An icy Solar System body that can develop a diffuse coma and tail when heated by the Sun.
Rapid brightness and color fluctuations caused by atmospheric turbulence along the line of sight to a star or other compact source.
Bending of light through layers of air with different density, altering the apparent position of objects near the horizon.
An atmospheric layer where temperature increases with height, which can affect radio propagation and visual refraction.
An apparent displaced or distorted image caused by refraction through air layers with strong temperature gradients.
A smooth lens- or saucer-shaped cloud that forms in standing atmospheric waves, often near mountains.
Very high-altitude ice clouds visible in deep twilight when lower layers of the atmosphere are already dark.
A bright spot produced by sunlight refracting through ice crystals, often appearing on either side of the Sun.
A vertical column of light caused by reflection from flat ice crystals in the atmosphere.
A ring or arc around the Sun or Moon created by refraction through atmospheric ice crystals.
Light emitted in the upper atmosphere when charged particles interact with atmospheric gases, often forming arcs, curtains or diffuse glows.
A brief high-altitude electrical discharge above thunderstorms, often red and vertically structured.
Very brief expanding rings of upper-atmospheric light associated with strong lightning electromagnetic pulses.
A rapid atmospheric electrical discharge that can illuminate clouds, create unusual reflections or produce brief luminous structures.
A rare and incompletely understood reported luminous atmospheric phenomenon; individual claims require careful case-by-case evidence.
A perceptual effect in which the Moon can look unusually large near the horizon even though its angular size changes very little.
Descriptive shape labels used in witness reports and archives. They describe appearance, not necessarily physical construction.
An informal label for a round or point-like luminous object. In imagery, an apparent orb can also result from blur, bokeh, dust or an unresolved light source.
A report describing a three-dimensional round or ball-like appearance.
A report describing a flattened circular or saucer-like appearance.
A historical popular term for disc-shaped UFO reports, widely used from the late 1940s onward.
A report describing a triangular outline or three-light triangular arrangement.
A report describing a bent-wing, chevron or V-shaped appearance.
A historical descriptive label for a long object with rounded ends.
A report describing an elongated tube-like form.
An informal modern label for a smooth oblong or capsule-like reported shape.
A report describing an elliptical or egg-like outline.
A report describing a rhombus- or diamond-like silhouette.
A report describing a rectangular or box-like outline.
A source too small or distant to resolve as a shape, appearing only as a point of light.
Multiple nearby lights or objects perceived as a group rather than a single isolated source.
Several objects or lights reported as moving or arranged in a recognizable pattern.
A report in which the observed form does not match a simple geometric shape.
A reported apparent change in shape; this can reflect a real change, perspective, focus, exposure, sensor processing or multiple unresolved lights.
A description indicating that an object or phenomenon appeared to emit or strongly radiate light.
A visual description suggesting a reflective metal-like surface; it is not a material identification by itself.
A visual description in which background light or scenery appears partially visible through the observed form.
Organizations, archives and historical programs commonly encountered when researching official UAP/UFO records.
The U.S. Department of Defense office responsible for receiving, analyzing and resolving UAP reports across domains under its statutory and policy authorities.
A U.S. Department of Defense task force that preceded later UAP organizations and focused on understanding UAP reports affecting national security and flight safety.
A short-lived U.S. Department of Defense organization established after UAPTF and later superseded by AARO.
The U.S. office that coordinates the Intelligence Community and has participated in statutory UAP reporting to Congress.
The U.S. federal department responsible for national defense. Historical records may use older department names depending on period and source.
A U.S. government release system for declassified UAP/UFO-related records and media published in tranches beginning in 2026.
The U.S. civil space agency. NASA has conducted public work concerning UAP data and also produces extensive space and Earth-observation data relevant to case analysis.
The U.S. civil aviation authority responsible for airspace regulation, flight safety and systems including national ADS-B infrastructure.
A binational U.S.-Canadian command responsible for aerospace warning, aerospace control and maritime warning for North America.
The U.S. federal archive that preserves and provides access to historical government records, including collections containing UFO/UAP-related documents and media.
The U.S. federal law that provides a process for requesting agency records, subject to statutory exemptions and exclusions.
The UK government department responsible for defense. Historical UK UFO files and reports have been released through official channels and The National Archives.
The United Kingdom’s air force, referenced in numerous historical aviation and UFO-related records.
The U.S. military air service that ran several major historical UFO investigations, including Project Blue Book.
The U.S. Navy; modern UAP reporting became especially prominent through naval aviation incidents and released sensor videos.
The U.S. military service focused on space operations, including space-domain awareness and tracking of resident space objects.
An early U.S. Air Force investigation of reported unidentified aerial phenomena, established in 1948.
The U.S. Air Force investigation that followed Project Sign and preceded Project Blue Book.
The long-running U.S. Air Force program that investigated UFO reports from 1952 until its termination in 1969.
A University of Colorado study of UFOs led by physicist Edward Condon in the 1960s and sponsored by the U.S. Air Force.
A 1953 scientific advisory panel convened under CIA auspices to assess UFO reports and their national-security implications.
A historical military reporting procedure for certain significant sightings by aircrews and other observers.
A historical communications publication associated with procedures for reporting vital intelligence sightings, including unusual aerial observations.
A Hynek classification for a relatively close visual UFO observation without reported physical effects or occupants.
A Hynek classification for a close observation accompanied by reported physical effects such as traces, interference or physiological effects.
A Hynek classification for a close observation in which occupants or entities are reported. It is a historical UFO classification, not a modern government standard.
The authorized removal of national-security classification restrictions from information or records.
A marking indicating the security classification of information. A classification label describes handling requirements, not the truth or evidentiary strength of a claim.
Useful terms for understanding how UAPLocations presents official files, provenance and historical records.
A record created close to the event or by the organization/person directly involved, such as an original report, image, log or memorandum.
A later analysis, article or summary based on primary records or other reporting.
Information documenting where a record came from, which agency/archive held it and how it reached the current collection.
An archival grouping of records associated with a U.S. federal agency or organizational unit, commonly used by NARA.
A group of records maintained together because they result from the same function, filing system or recordkeeping activity.
A unique identifier used by NARA for archival descriptions and records in the National Archives Catalog.
The metadata entry describing an archival item, file, series or collection, often including dates, creators, scope and access information.
A guide that describes the structure and contents of an archive collection to help researchers locate relevant material.
A digital reproduction of a physical or analog archival record.
A record originally created in digital form rather than scanned or converted from analog media.
A copyright status in which material is not protected by copyright in a given jurisdiction or protection has expired. Public availability alone does not automatically mean public domain.
A UK licensing framework that permits reuse of covered public-sector information subject to its terms and required attribution.
A Creative Commons licence that permits broad reuse provided the required attribution and licence conditions are followed.
A credit identifying the creator, archive or source as required by a licence, rights notice or good research practice.
Documentation of who collected, possessed, transferred or processed an item of evidence. A strong chain of custody helps assess authenticity and integrity.
A computed value used to verify that a digital file has not changed between copies or processing steps.
Software extraction of machine-readable text from images or scans of documents. OCR can contain recognition errors and should be checked against the original.
A link to the agency, archive or publisher from which the indexed record originates.
An identifier used to distinguish a record within a database, archive or reporting system.
A record allowed to appear in search-engine indexes; this is a publishing/SEO status rather than an evidentiary classification.
UAP means Unidentified Anomalous Phenomena. It is a status/description for observations not yet identified from the available information, not a synonym for alien spacecraft.
LEO means Low Earth Orbit, generally the orbital region from roughly 160 to 2,000 km above Earth. The ISS and many Starlink satellites operate in LEO.
A Two-Line Element Set is a legacy format for orbital data. Combined with the SGP4 propagator it can be used to estimate where a cataloged satellite or other tracked object should be.
A case supported by more than one independent sensor or evidence stream, for example radar plus infrared imagery. Corroboration can improve confidence that a detection was not caused by one sensor alone.
An elevation below 0° places the calculated object below the observer’s local horizon. UAPLocations does not draw such aircraft, satellites or celestial objects as visible targets in the Live Sky Scanner.
No. An unresolved case simply lacks a sufficiently supported identification after review and can remain unresolved because the available data are incomplete or ambiguous.
This glossary is an editorial reference rather than a replacement for source-agency definitions. For technical and current terminology, compare the original sources: