The words in the file.
106 UFO and UAP terms, from AARO to the Zoo hypothesis. One or two plain sentences each, a source where it is a fact, and a label where it is only lore.
UAP is the government's current word for what most people still call a UFO: something seen or detected that nobody can yet identify. Most of the terms below come from three places: official records, the science of looking for life elsewhere, and the lore that grew up around sightings. Each entry says which one it is.
106 terms
Numbers
- 3I/ATLAS
The third known interstellar object, a comet first reported on July 1, 2025 by the ATLAS survey telescope in Chile. NASA classes it as a comet.
A
- AARO (All-domain Anomaly Resolution Office)
The Pentagon office that collects and analyzes UAP reports from the military and intelligence agencies. The Department of Defense announced it on July 20, 2022, replacing an earlier group.
- AATIP (Advanced Aerospace Threat Identification Program)
A name widely used for Pentagon UAP work in the late 2000s and early 2010s. AARO's 2024 history says AATIP was never an official program name and was used interchangeably with AAWSAP.
Read: Government UFO programs Source: AARO Historical Record Report, Vol. 1
- AAWSAP (Advanced Aerospace Weapon System Applications Program)
A Defense Intelligence Agency program set up in 2009 through a contract with a private company, funded with $22 million from Congress and ended in 2012. It studied future aerospace threats, including UAP.
Read: Government UFO programs Source: AARO Historical Record Report, Vol. 1
- Abduction
- Claim
A reported experience of being taken by non-human beings, often at night and often recalled later. No abduction has been verified by physical evidence.
- Alien implant
- Lore
An object some abduction accounts say was placed in the body during contact. Objects removed and tested so far have not been shown to be of non-human origin.
- Ancient astronaut theory
- Theory
The idea that visitors from elsewhere shaped early human cultures and monuments. Archaeologists do not accept it, and it rests on reinterpreting old texts and sites.
- Anunnaki
- Lore
A group of gods in the ancient Mesopotamian pantheon. Zecharia Sitchin's 1976 book The 12th Planet recast them as visitors from another planet, a reading scholars reject.
Read: Anunnaki theory Source: Oracc, University of Pennsylvania
- Arcturian
- Lore
Beings said to come from the star Arcturus, found mostly in channeled and New Age writing. There is no physical evidence for them.
- Area 51
A secret Air Force test site at Groom Lake, Nevada, used for spy planes such as the U-2. The CIA acknowledged it in a declassified history released in 2013.
Read: Government UFO programs Source: National Security Archive
B
- Ball lightning
A rare glowing sphere reported during thunderstorms, usually lasting seconds. Scientists still have no accepted theory for what causes it.
- Biosignature
Any sign that life is or was present, such as a gas in a planet's air that living things produce. Scientists look for them on Mars, icy moons and distant planets.
Read: Are we alone? Source: NASA Technosignatures Workshop report
- Black triangle
A report of a large, dark, triangular craft with lights at its corners, often slow and silent. Aircraft in formation, blimps and military planes explain many cases.
- Breakthrough Listen
The largest privately funded search for signals from other civilizations, announced on July 20, 2015 with $100 million over ten years.
Read: The SETI post-detection protocol Source: Breakthrough Initiatives
C
- CADORS (Civil Aviation Daily Occurrence Reporting System)
Transport Canada's database of aviation safety occurrences. Pilot and air traffic reports of unidentified objects are logged there.
Read: Report a UFO in Canada Source: Sky Canada Project report
- Canadian UFO Survey
An annual count of Canadian UFO reports compiled by Ufology Research since 1989. The 2025 survey counted 1,052 reports, and 3.42 percent stayed unexplained.
Read: Report a UFO in Canada Source: The 2025 Canadian UFO Survey
- CE1 (close encounter of the first kind)
A sighting of an object at close range, within about 200 metres, with no physical effects left behind.
Read: Close encounter types Source: Canadian UFO Survey definitions
- CE2 (close encounter of the second kind)
A close encounter that leaves physical effects, such as marks on the ground, burns or interference with engines or radios.
Read: Close encounter types Source: Canadian UFO Survey definitions
- CE3 (close encounter of the third kind)
A close encounter in which the witness reports seeing figures or beings with the object.
Read: Close encounter types Source: Canadian UFO Survey definitions
- CE4 (close encounter of the fourth kind)
- Claim
A reported abduction or contact experience. It was added to the scale by later researchers, not by its creator.
Read: Close encounter types Source: Canadian UFO Survey definitions
- CE5 (close encounter of the fifth kind)
- Lore
Contact that people try to start on purpose, through meditation or signaling. The idea is promoted by contact groups and has no verified result.
- CIRVIS (Communications Instructions for Reporting Vital Intelligence Sightings)
A standing instruction for pilots in Canada to report unusual aerial activity, including unidentified objects. Transport Canada's aeronautical manual still refers to it.
Read: Report a UFO in Canada Source: The 2025 Canadian UFO Survey
- Condon Report
A University of Colorado study of UFO reports paid for by the Air Force in the late 1960s. It concluded that further study was unlikely to be useful and helped end Project Blue Book.
- Contactee
- Lore
A person who says they are in ongoing, friendly contact with beings from elsewhere and passes on their messages. None of these accounts has been independently verified.
- Crash retrieval
- Claim
The claim that governments have recovered crashed non-human craft and tried to reverse-engineer them. David Grusch testified to it in 2023. AARO found no evidence of any such program.
D
- Dark forest
- Theory
The idea that civilizations stay silent because revealing yourself invites attack. It comes from Liu Cixin's 2008 science fiction novel The Dark Forest.
- Designation
- DISCLOSURE term
The role the DISCLOSURE classification assigns you after ten questions: Sentinel, Diplomat, Scholar or Survivor.
- Diplomat
- DISCLOSURE term
The DISCLOSURE role for de-escalation. A group copies its steadiest person, and the Diplomat chooses to be that person.
- Disclosure
The hoped-for moment when a government confirms what it knows about UAP. In practice so far it has meant hearings, reports and file releases, none confirming non-human contact.
- Disclosure anxiety
Worry or dread about what an official announcement on aliens might mean. It is a common reaction, not a medical diagnosis.
- Drake equation
A way of estimating how many civilizations in our galaxy might be sending signals, by multiplying seven factors. Frank Drake wrote it in 1961 for the first SETI meeting.
- Drone
An uncrewed aircraft, from a toy quadcopter to a military plane. At night its lights can blink, hover and change direction in ways that look strange from the ground.
E
- Earthquake lights
Glows, flashes or balls of light reported around earthquakes. Scientists disagree on how many reports are real, and some were arcing power lines.
- Experiencer
A person who reports a contact or encounter experience. Many prefer it to abductee because it does not assume what happened.
- Extraterrestrial hypothesis (ETH)
- Theory
The idea that some UFOs are craft from other worlds. No official investigation has found evidence for it.
Read: Are we alone? Source: AARO Historical Record Report, Vol. 1
F
- Fermi paradox
The gap between how likely other civilizations seem and the total lack of evidence for them. It is named for physicist Enrico Fermi, who asked where everybody was over lunch in 1950.
Read: The Fermi paradox explained Source: Los Alamos report LA-10311-MS
- First Contact (the sealed file)
- DISCLOSURE term
The fifth DISCLOSURE designation. It is not issued. It appears.
- Five observables
- Claim
A list of flight traits said to set some UAP apart, including sudden acceleration, hypersonic speed without visible propulsion, low observability and transmedium travel. The 2023 UAP Disclosure Act text lists six such observables.
- FLIR (forward-looking infrared)
A heat-sensing camera on military aircraft. It is also the nickname of one of three Navy videos the Pentagon released in 2020, filmed in November 2004.
- Flying saucer
The press term that followed pilot Kenneth Arnold's report of fast objects near Mount Rainier in June 1947. It came before the Air Force adopted UFO.
Read: Government UFO programs Source: AARO Historical Record Report, Vol. 1
- Foo fighters
The name Allied aircrews gave to unexplained lights that seemed to follow their planes over Europe in 1944 and 1945.
Read: Government UFO programs Source: New York Times, January 2, 1945
G
- Galileo Project
A Harvard research project led by astronomer Avi Loeb that uses its own telescopes and sensors to look for technology from elsewhere. It launched in July 2021.
- Gimbal
One of three Navy videos the Pentagon released in 2020, filmed in January 2015, showing an object that appears to rotate. Analysts disagree on whether the rotation is the object or the camera mount.
- GoFast
One of three Navy videos the Pentagon released in 2020, filmed in January 2015, showing a small object that seems to skim fast over the ocean. In February 2025 AARO resolved it: the object was about 13,000 feet up moving with the wind, and the speed was an effect of the jet's own motion.
- Great Filter
- Theory
The idea that some step between dead matter and a star-travelling civilization is so hard that almost nothing passes it. Economist Robin Hanson set it out in 1998.
- Grey
- Lore
A small grey being with a large head and large black eyes, the best-known figure in abduction lore. No specimen or verified image exists.
H
- Hybrid
- Lore
A being said to be part human and part alien, found in some abduction accounts. There is no biological evidence for one.
- Hynek scale
The close encounter scale named for astronomer J. Allen Hynek, the lead scientific consultant to Project Blue Book. He sorted close sightings into the first, second and third kind.
Read: Close encounter types Source: AARO Historical Record Report, Vol. 1
I
- IFO (identified flying object)
Investigators' shorthand for a sighting that turned out to have an ordinary cause, such as a plane, a planet or a balloon.
- Insectoid
- Lore
Any insect-like being in encounter reports, a group that includes the Mantids. Reports only, with no physical evidence.
- Interdimensional hypothesis
- Theory
The idea that some phenomena come from another dimension or layer of reality rather than another planet. It cannot be tested with current science.
- Iris print
- DISCLOSURE term
The iris DISCLOSURE draws from your answers during the classification. Every answer changes it, so two people with different answers never get the same one.
- ISS (International Space Station)
The crewed station in low orbit. From the ground it looks like a very bright star moving steadily, with no flashing lights, a few hours before sunrise or after sunset.
K
- Kardashev scale
A ranking of civilizations by how much energy they use: Type I a planet's worth, Type II a star's, Type III a galaxy's. Soviet astronomer Nikolai Kardashev proposed it in 1964.
Tool: Drake and Kardashev calculator Source: Soviet Astronomy, 1964
M
- Majestic 12 (MJ-12)
Documents that surfaced in the 1980s describing a secret panel formed to handle a crashed saucer. An Air Force investigation determined the document to be a fake.
- Mantid
- Lore
A tall, insect-like being resembling a praying mantis, described in some abduction accounts. Reports only.
- Missing time
- Claim
A stretch of time a witness cannot account for after a sighting. Stress, fatigue and ordinary memory gaps explain many cases, and some witnesses read it as abduction.
- MUFON (Mutual UFO Network)
A US membership group of volunteer UFO investigators that takes reports from many countries. It began on May 31, 1969 as the Midwest UFO Network.
N
- NASA UAP study
An independent team of outside experts that NASA asked to look at UAP. Its final report, published September 14, 2023, called for better data and found no evidence that UAP are extraterrestrial.
- NDAA (National Defense Authorization Act)
The yearly US defense law. The version signed on December 22, 2023 ordered agencies to send UAP records to a new collection at the National Archives.
- NHI (non-human intelligence)
A term for any intelligent lifeform that is not human, whatever its origin. The 2023 Schumer-Rounds amendment defined it as any sentient intelligent non-human lifeform, whatever its origin.
Read: The disclosure timeline Source: congress.gov, S.Amdt.797
- Nordic
- Lore
A tall, fair-haired being that looks almost human, described by 1950s contactees and later witnesses. Reports only.
- NUFORC (National UFO Reporting Center)
A US civilian center that collects sighting reports through an online form. Canadians file there too, and the Canadian UFO Survey counts those reports.
O
- ODNI (Office of the Director of National Intelligence)
The office that oversees the US intelligence agencies. It published a preliminary assessment on UAP in June 2021 and issued guidance on UAP disclosure in July 2026.
- Ontological shock
The jolt of learning something that upends your picture of how the world works. David Grusch used the phrase about UAP in his 2023 testimony.
Read: Ontological shock explained Source: Grusch statement, July 26, 2023
- Orb
A round light or glowing ball reported in the sky or seen in a photo. Balloons, lanterns, drones and dust or insects near a camera lens explain most.
- 'Oumuamua
The first object confirmed to come from another star system, found on October 19, 2017 by the Pan-STARRS1 telescope in Hawaii. Its odd shape and motion drew wide debate.
P
- Phoenix Lights
A mass sighting over Arizona on March 13, 1997, including a reported V-shaped formation of lights. The official explanation for part of it is military flares.
- Pleiadian
- Lore
A human-looking being said to come from the Pleiades star cluster. The idea spread from Swiss contactee Billy Meier, who says his Pleiadian contacts began in 1975.
- Post-detection protocol
The plan scientists agreed on for what to do if a signal from another civilization is ever found: verify it, tell other researchers, then tell the public.
- Project Blue Book
The Air Force's public UFO investigation from 1952 to December 17, 1969. It logged 12,618 sightings and left 701 unidentified.
- Project Mogul
A classified balloon program for detecting Soviet nuclear tests. A 1994 Air Force report said a Mogul balloon was the source of the Roswell debris.
- Project Sign and Project Grudge
The Air Force's first UFO studies, Sign in 1948 and Grudge in 1949. They came before Project Blue Book.
Read: Project Blue Book explained Source: AARO Historical Record Report, Vol. 1
- PURSUE (Presidential Unsealing and Reporting System for UAP Encounters)
The Department of War program that publishes reviewed UAP files at war.gov/UFO. The first batch of 162 files went up on May 8, 2026.
R
- Record Group 615 (RG 615)
The National Archives record group that holds the UAP Records Collection. Agencies transfer files to it, and the Archives posts them online on a rolling basis.
- Rendlesham Forest
A December 1980 case in which US Air Force personnel near RAF Woodbridge and RAF Bentwaters in Suffolk, England reported lights and a craft in the forest.
- Reptilian
- Lore
A reptile-like humanoid found in abduction and conspiracy lore. Reports and claims only.
- Rio Scale
A 0 to 10 scale for rating how important a claimed detection of alien life would be. Iván Almár and Jill Tarter proposed it in 2000, and it was revised in 2018.
- Robertson Panel
A panel of scientists convened by the CIA in January 1953 to review UFO reports. Its brief was to judge whether the reports pointed to any threat to national security.
Read: Government UFO programs Source: AARO Historical Record Report, Vol. 1
- Roswell
The 1947 New Mexico case in which the Army announced a recovered flying disc, then called it a weather balloon. The Air Force later tied the debris to Project Mogul.
S
- S-4
- Claim
A site near Area 51 where Bob Lazar has said since 1989 that he worked on alien craft. His claims have not been verified.
- San Marino Scale
A 1 to 10 scale for rating the risk of a message sent from Earth into space, including a reply to a signal. Iván Almár proposed it in 2005.
- Scholar
- DISCLOSURE term
The DISCLOSURE field analyst role. The Scholar records the time, direction and detail, because the account written down that night is the one that survives.
- Sentinel
- DISCLOSURE term
The DISCLOSURE protector role. Sentinels step between a threat and other people, and their training is knowing when not to step forward.
- SETI (search for extraterrestrial intelligence)
The science of looking for signals or technology from other civilizations, mostly with radio and optical telescopes. The SETI Institute was founded in 1984.
Read: The SETI post-detection protocol Source: SETI Institute
- Shag Harbour
A 1967 Nova Scotia case in which witnesses reported something coming down over the water. Library and Archives Canada calls it Canada's most famous UFO incident, investigated by the RCMP and Canadian Forces.
Read: Report a UFO in Canada Source: Library and Archives Canada
- Sirian
- Lore
A being said to come from the star Sirius, found in channeled writing and some ancient-astronaut books. There is no physical evidence.
- Sky Canada Project
A study by Canada's Chief Science Advisor on how UAP reports are handled. Its June 2025 report found no official way for Canadians to report sightings and recommended a lead federal agency.
- Sky lantern
A small paper hot-air balloon lifted by a flame. From a distance a group of them looks like slow orange lights drifting in a line, then winking out.
- Sleep paralysis
Being unable to move for a short time while falling asleep or waking up, sometimes with the feeling or vision of someone in the room. It is common and harmless, and it matches many bedroom abduction accounts.
Read: Sleep paralysis or abduction? Source: Cleveland Clinic
- Sprites
Red flashes of light high above large thunderstorms, lasting a split second. The first image of one was captured in 1989.
- Starlink train
A line of recently launched Starlink satellites crossing the sky one after another, like a string of moving stars. Each one is a small internet satellite reflecting sunlight.
- Survivor
- DISCLOSURE term
The DISCLOSURE self-preservation role. Survivors read the exits first and know when leaving is the calm choice.
T
- Tall White
- Lore
A very tall, pale being described by Charles Hall, who says he met them while stationed at a Nevada test range. His books are the only source.
- Technosignature
A detectable sign of technology made by life elsewhere, such as a narrow radio signal or industrial gases in a planet's air.
Read: Are we alone? Source: NASA Technosignatures Workshop report
- Ten-second drill
- DISCLOSURE term
The DISCLOSURE readiness drill: six scenes on a blackout night, with ten seconds to make each call.
- Tic Tac
The nickname for a smooth white object Navy pilots reported near the USS Nimitz in November 2004. Commander David Fravor described it under oath in 2023.
- Transmedium
Able to move between air, space and water. US law includes transmedium objects in its definition of UAP.
U
- UAP (unidentified anomalous phenomena)
The US government's term for detections in the air, sea, space or across them that cannot yet be attributed to a known source. It replaced UFO in official use.
- UAP Disclosure Act
A bill to force release of government UAP records under an independent review board. A reduced version became law in December 2023, and the fuller act passed the House on July 22, 2026 but not the Senate.
- UAP Records Collection
The collection of government UAP records at the National Archives, created by the 2023 defense law. Agencies send files to it and the public can read them online.
- UAP Task Force (UAPTF)
A Navy-led Pentagon group set up in August 2020 to study UAP that could threaten national security. Its work passed to AARO in 2022.
- UFO (unidentified flying object)
Any object in the sky its observer cannot identify. The Air Force adopted the term in the 1950s, and in everyday speech it has come to mean an alien craft.
V
- Venus
The brightest planet, often low on the horizon near dawn or dusk. It is one of the most common things reported as a UFO.
Tool: What did I just see? Source: AARO Historical Record Report, Vol. 1
W
- Wow! signal
A strong, narrow radio signal picked up by Ohio State's Big Ear telescope on August 15, 1977. Astronomer Jerry Ehman circled it and wrote Wow! on the printout. It was never detected again.
Z
- Zoo hypothesis
- Theory
The idea that other civilizations know we are here and choose not to make contact, as keepers watch animals in a zoo. John Ball proposed it in 1973.
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How this glossary is written
Official findings are stated as findings. Claims made by witnesses, whistleblowers and authors are labeled as claims. Beings and origin stories that appear only in reports and books are labeled as lore, because no government or scientific body has confirmed any of them. Terms marked DISCLOSURE term belong to this site's own classification and drill.
Sources were checked on September 28, 2026. If a definition is wrong or out of date, write to team@getdisclosure.app and it will be fixed.
Knowing the words is not knowing the job.
When something is in the sky, nobody will ask you to define transmedium. They will look at whoever moves first. Ten questions find what you would do.