Alien & UFO Glossary: Terms from AARO to Zeta Reticuli

The All-domain Anomaly Resolution Office, the Pentagon office created in 2022 to collect and investigate reports of unidentified anomalous phenomena across the U.S. military. It publishes annual reports and a historical review, and is the successor to AATIP and the UAP Task Force.

The Advanced Aerospace Threat Identification Program, a Pentagon effort to study unidentified aerial phenomena that ran from about 2007 to 2012 and became public in December 2017 through reporting by The New York Times. Luis Elizondo says he ran it.

A person who believes they were taken by non-human beings, usually against their will, and often remembers the event only partially or under hypnosis. The term entered common use after the Betty and Barney Hill case of 1961.

A name coined by the critic Mark Dery in 1993 for the tradition in Black art and music of imagining outer space and the future as a place of freedom, and of using the alien and the spaceship to speak about a history of abduction and displacement. Its founders are Sun Ra, who said he was from Saturn, and George Clinton, whose Parliament-Funkadelic landed a Mothership on stage; the tradition runs through Outkast, Janelle Monáe and Black Panther.

A theoretical faster-than-light propulsion concept proposed by physicist Miguel Alcubierre in 1994: a bubble of spacetime that contracts ahead of a ship and expands behind it. It is consistent with general relativity on paper but would require exotic negative-energy matter nobody knows how to make.

The idea, popularized by Erich von Däniken's 1968 book Chariots of the Gods?, that extraterrestrials visited Earth in prehistory and were remembered as gods, and that monuments like the pyramids and the Nazca lines record their presence. Archaeologists reject it.

Deities of Sumerian and Babylonian mythology. In Zecharia Sitchin's books, beginning with The 12th Planet (1976), they become aliens from a planet called Nibiru who engineered humanity as a labor force, a reading Assyriologists say misrepresents the texts.

The U.S. Air Force facility at Groom Lake, Nevada, where the U-2, A-12 and F-117 were developed in secret. Its association with recovered alien craft comes largely from Bob Lazar's 1989 claims about a nearby site he called S-4.

The Ohio State University radio telescope in Delaware, Ohio, that recorded the Wow! signal on August 15, 1977 during a SETI survey. It was demolished in 1998.

Any substance, pattern or gas that indicates past or present life, such as a mineral texture left by microbes or an atmospheric gas that only biology maintains. Every "potential biosignature" so far has a non-biological explanation that has not been ruled out.

The U.S. Air Force's official UFO investigation from 1952 to 1969, successor to Projects Sign and Grudge. It logged 12,618 sightings, 701 of them left unexplained, and its files are at the National Archives.

The man who claimed in 1989 to have worked on reverse-engineering alien craft at S-4 near Area 51, powered by a stable form of element 115. His credentials remain unverified and his story unchanged for over thirty years.

"Close encounter of the fifth kind": human-initiated contact with extraterrestrials, usually through group meditation and signalling, as promoted by Steven Greer since the 1990s. No result of a CE-5 session has been scientifically verified.

The rock in Jezero Crater sampled by NASA's Perseverance rover in July 2024 whose organic molecules and "leopard spot" mineral patterns were described in 2025 as a potential biosignature, the strongest candidate for past life on Mars so far, and not a confirmation.

J. Allen Hynek's 1972 classification of UFO reports by proximity: a close encounter of the first kind is a sighting within about 500 feet, the second leaves physical traces, and the third involves visible occupants. Later writers added abduction (fourth) and human-initiated contact (fifth).

The University of Colorado's 1968 study of UFOs for the U.S. Air Force, led by physicist Edward Condon, which concluded that further study was not justified and led to the closing of Project Blue Book, even though about a third of its own cases stayed unexplained.

Someone who claims ongoing, usually friendly, communication with extraterrestrials, in person or telepathically. The 1950s contactees such as George Adamski described tall, benevolent "space brothers," the origin of the Nordic alien type.

The alleged recovery of downed non-human craft and their occupants by military teams, the claim at the center of Roswell and of David Grusch's 2023 testimony that the U.S. holds retrieved craft in a compartmented program.

A pattern flattened into a field of grain, most often in southern England. Doug Bower and Dave Chorley confessed in 1991 to making hundreds with planks and rope; formations have grown more elaborate since, and artists openly claim most of them.

The species of living machines from the planet Cybertron in Transformers, Autobots and Decepticons alike: animated by a spark, fuelled by Energon, and able to reshape themselves into scanned vehicles. They are aliens, not human-built robots.

A proposed answer to the Fermi paradox, named after Liu Cixin's novel: civilizations stay silent because any that reveals itself risks being destroyed by a neighbor that cannot afford to trust it.

"The Bell": a bell-shaped Nazi antigravity device described by Polish writer Igor Witkowski in 2000 from interrogation transcripts nobody else has seen. No wartime record of it exists; its supposed test rig in Silesia is a cooling-tower base.

In UFO circles, the anticipated official admission by governments that non-human intelligence is real and that some of what they know has been withheld. The word covers everything from routine declassification to the "full disclosure" of the movement's hopes.

Frank Drake's 1961 formula for estimating the number of communicating civilizations in the galaxy by multiplying factors such as the rate of star formation, the fraction of stars with planets, and the lifetime of a technological society. Its value is the conversation it organizes, not the number.

Moscovium, a synthetic element first produced in 2003 whose isotopes decay in fractions of a second. Bob Lazar claimed in 1989 that a stable form powered the craft at S-4; no stable isotope exists.

The encounter described by U.S. Air Force security policemen Mario Woods and Michael Johnson at a Minuteman missile site in South Dakota: a huge glowing craft, small grey beings, and missing time. Johnson first spoke publicly in 2026.

Jupiter's ice-covered moon, beneath whose crust lies a salty ocean holding more water than all of Earth's. NASA's Europa Clipper, launched in 2024, arrives in 2030 to assess whether it could support life.

A planet orbiting a star other than the Sun. Nearly six thousand are confirmed, a few dozen of them rocky worlds in their star's habitable zone, where liquid water could exist at the surface.

The term many people who report contact or abduction now prefer to "abductee," reflecting accounts that are not always unwilling or frightening. Popularized by researchers and surveys in the 2010s.

The wheeled, winged vision of Ezekiel 1, read by ancient-astronaut writers (and NASA engineer Josef Blumrich in 1974) as a spacecraft. Scholars identify it as the throne-chariot of God, drawn from Babylonian throne imagery; it is the root of Jewish merkabah mysticism.

The tension between the expectation that intelligent life should be common in a galaxy of hundreds of billions of old stars and the complete absence of evidence for it, summed up in Enrico Fermi's 1950 question: "Where is everybody?"

The first meeting between humanity and an extraterrestrial intelligence, as an event, a genre and a set of real protocols. SETI's declaration of principles covers what to do with a detected signal; fiction has staged it as an invasion, a landing, a language lesson and, in Star Trek, a Vulcan stepping out of a ship in Montana on April 5, 2063.

A cluster of UFO reports concentrated in one place and time, such as Washington, D.C. in July 1952, France in autumn 1954, or Belgium in 1989–90. Also called a wave.

The press's name for UFOs after Kenneth Arnold's June 1947 sighting, in which he said the objects moved "like a saucer skipped across water." The shape came from the headline, and witnesses reported discs for decades after.

Balls of light that Allied and Axis aircrews reported following their aircraft in 1944–45, named from a comic-strip catchphrase. Never explained; St. Elmo's fire and ball lightning are the usual candidates.

A large design made on the ground by arranging or removing stones or earth, meant to be seen from a height. The Nazca lines of Peru are the most famous; the 2024 AI-assisted survey there added 303 new ones.

Thousands of reports of rocket- or missile-like objects over Scandinavia in 1946, investigated by Swedish and British intelligence as possible Soviet tests and never resolved; most are now attributed to meteors.

The three U.S. Navy infrared videos of unidentified objects, recorded in 2004 and 2015 and officially released by the Pentagon in 2020. They remain the best-known "authenticated" UAP footage; what they show is still argued over.

Robin Hanson's 1996 idea that some step between dead matter and a galaxy-spanning civilization is almost impossibly hard, which would explain the silence. If the filter is behind us, we are rare; if ahead, we are in trouble.

The archetypal aliens of modern ufology: small, grey-skinned, large-headed beings with black almond eyes, said to come from Zeta Reticuli. Their image dates to the Hill case and became universal with the 1987 cover of Communion.

The former Air Force intelligence officer who told Congress in July 2023, under oath, that the U.S. runs a decades-long crash-retrieval and reverse-engineering program and has recovered "non-human biologics." He says his evidence was given to the inspector general in classified form.

The range of distances from a star at which a planet with a suitable atmosphere could keep liquid water on its surface; also called the Goldilocks zone. Being in it is necessary for Earth-like life, not sufficient.

Lt. Col. Charles Halt's January 1981 memorandum "Unexplained Lights" to the British Ministry of Defence, summarizing the Rendlesham Forest sightings. Released under FOIA in 1983, it is the key document of Britain's best-known UFO case.

A series of Nazi flying saucers that exist only in drawings and typed specifications circulated from the late 1980s by a German neo-Nazi occult circle. Every Haunebu image online descends from those documents; none appears in any wartime source.

The seven-limbed aliens of Ted Chiang's "Story of Your Life" and the film Arrival, whose circular written language, Heptapod B, records a whole thought at once and changes how its readers experience time. Named from the Greek for "seven feet."

A collective consciousness shared by every member of a species, so that individuals act as one will: the Borg Collective, the Zerg Swarm, the Xenomorph hive. Abduction accounts describe the Greys and the Mantis beings the same way, one of the clearest borrowings between fiction and the reports in either direction.

A circular gap in a cloud deck, usually left by an aircraft whose passage triggers ice crystals to fall out. The hole witnesses saw at O'Hare in 2006 is the case's most distinctive, and most argued-over, detail.

Magneto's name for mutants in The X-Men #1 (1963), borrowed from the pulps: a supposed next stage of humanity born with an X-gene. The comics keep the phrase in the mouths of the mutants who want a war; real genetics has no such category.

The claim, developed by abduction researchers Budd Hopkins and David Jacobs, that the Greys are breeding human-alien hybrids using material taken from abductees. It rests entirely on hypnotically recovered testimony.

The radio emission of neutral hydrogen at 1420.4 MHz, or 21 centimeters. SETI searches watch it because any technological civilization would know it; the Wow! signal was recorded right beside it.

The alleged unacknowledged special access program described in a roughly twelve-page document that reached Congress and journalists in 2024, said to compartmentalize UAP imagery and incident data. Matthew Brown identified himself as its author in 2025; the Pentagon has not acknowledged it.

A small object some abductees believe was placed in their bodies by aliens. The late podiatric surgeon Roger Leir removed several; laboratory analyses have found ordinary materials and no proof of non-human origin.

A general term for insect-like beings in encounter reports, most often the tall, praying-mantis-shaped "Mantids" abductees describe as overseers of the Greys.

The story in which aliens arrive to conquer, colonize or consume Earth, begun by H.G. Wells's The War of the Worlds in 1897 and remade for every decade's fear since. Its opposite, the benevolent visitor, is the contactee story.

Japanese for "strange beast," and the name of the giant-monster genre Toho founded with Gojira in 1954. Godzilla, Mothra, Rodan and King Ghidorah are the classic kaiju; most are animals made vast by human technology, and the aliens among them are marked as exceptions.

Nikolai Kardashev's 1964 ranking of civilizations by the energy they command: Type I uses all of a planet's, Type II a star's, Type III a galaxy's. Humanity is roughly 0.7. It shapes what SETI expects an advanced civilization to look like.

Matthew Brown's 2026 term for a compartment whose members, he says, pass down oral tradition about U.S. government agreements with non-human intelligence. He presents it as what he was told, not what he saw documented.

The oldest slang for extraterrestrials, used for Martians in newspapers and pulps decades before the flying saucer and fixed as the American shorthand in August 1955, when the wire services headlined the Kelly, Kentucky farmhouse siege as an attack by little green men although the witnesses had described small silver beings. It survives in the three-eyed toys of Toy Story and in every cartoon Martian since.

A secret committee of scientists and officials supposedly created by President Truman in 1947 to manage recovered alien craft, known from documents that surfaced in the 1980s. The FBI and most researchers consider the documents forgeries.

Tall, thin, praying-mantis-like beings reported in a minority of abduction accounts, usually described as calm, ancient, and in charge. Also called Mantis aliens or insectoids.

Mysterious dark-suited visitors who, in stories dating to the 1950s, warn UFO witnesses into silence. Folklorists trace the motif to early ufology and the paranoia of the era; the films borrowed it.

"Military abduction": an experiencer's claim that human military personnel, alone or alongside aliens, took or interrogated them. No such program has ever been documented.

A gap in memory, from minutes to hours, that a witness cannot account for and that abduction researchers treat as the signature of a hidden encounter. Budd Hopkins' 1981 book of that name made the concept central to the field.

The CIA's mind-control research programme, approved in 1953 and run by the chemist Sidney Gottlieb, which tested LSD, hypnosis, sensory deprivation and electroshock on unwitting subjects for two decades; its files were ordered destroyed in 1973 and its outline was exposed by the press and the Church Committee in 1974 and 1975. It is the real programme behind the mind-control songs of Muse and Queensrÿche and the point where the brainwashing literature meets the abduction lore's military-abduction claims.

An initialism UAP whistleblower Matthew Brown used in an August 2026 interview and declined to expand when asked. Its meaning has not been confirmed by Brown, the Department of Defense, or any document; online expansions are speculation.

The official name, given in 2016, of element 115. First synthesized in Dubna, Russia, in 2003; every isotope decays in well under a second. See element 115.

The great wheel-shaped craft that Elijah Muhammad of the Nation of Islam taught, from the 1930s, was built by Black scientists from the vision of Ezekiel and circles the Earth carrying smaller planes, to be used at the end of the white world's rule; also called the Mother Wheel. Louis Farrakhan has described being carried aboard it in a vision in 1985. It is the most elaborate UFO doctrine of any American religion and a root of Afrofuturism's saucers.

In the reports, a large carrier craft from which smaller scout ships emerge: George Adamski described cigar-shaped motherships hundreds of feet long in the 1950s, and the word has been used for any oversized object since, including the mile-wide craft of the Phoenix Lights. In music it is the Parliament-Funkadelic spaceship that landed on stage in 1976 and now sits in the Smithsonian.

Hundreds of geoglyphs in Peru's coastal desert, made by the Nazca culture between about 500 BC and AD 500 by clearing dark stones to expose pale ground. Ritual pathways is the leading explanation; landing strips is not.

Three-fingered desiccated bodies from Peru, promoted since 2017 and shown to Mexico's Congress in 2023 as non-human. Peruvian forensic experts and mummy specialists describe them as ancient human and animal remains rearranged into new shapes; independent examination has not been allowed.

In Genesis 6, the offspring of the "sons of God" and human women, "the mighty men of old." Ancient-astronaut writers read them as alien-human hybrids; scholars read a fragment of older myth about divine beings and legendary giants.

Non-human intelligence: the deliberately neutral term modern disclosure advocates and legislators use instead of "aliens," so as not to assume the intelligence is extraterrestrial rather than, say, interdimensional or artificial.

Tall, fair, human-looking aliens with long blond hair, described by 1950s contactees and later called Pleiadians. Usually portrayed as benevolent and serene.

The National UFO Reporting Center, a volunteer organization in Washington State that has taken public UFO reports by hotline and web form since 1974 and publishes them online. Its report metadata is the source of the counts on Alien Tavern's sightings pages.

Small glowing spheres of light, the most commonly reported UAP shape in recent military and civilian reports, including the drone flaps of 2024. Explanations range from balloons and aircraft lights to genuinely unidentified objects.

The October 1973 encounter in which Mississippi fishermen Charles Hickson and Calvin Parker said robot-like beings floated them aboard a craft. A secretly recorded police-station conversation in which the two men, alone, remained terrified is the case's most cited evidence.

The mass sighting of March 13, 1997, when thousands of Arizonans reported a huge V-shaped formation of lights and, later that night, a row of lights over Phoenix identified as military flares.

A small, cheap amateur-radio balloon that can circle the globe for months at high altitude. A hobby club's missing pico balloon matched the object shot down over the Yukon in February 2023.

Nordic-type beings said to come from the Pleiades star cluster, a name introduced by Swiss contactee Billy Meier in the 1970s and adopted by New Age channelling. See Nordics.

The duplicates grown by the seed pods of Jack Finney's The Body Snatchers (1954) and its four film versions: identical to the person they replace, complete with memories, and empty of feeling. By extension, anyone suspected of having been quietly replaced.

A classified 1947 program that flew long trains of balloons and radar reflectors to listen for Soviet nuclear tests. The U.S. Air Force's 1994 report identified a Mogul array as the source of the Roswell debris.

The U.S. Air Force's first UFO investigations, in 1948 and 1949, predecessors of Project Blue Book. Sign reportedly drafted an "estimate" favoring the extraterrestrial hypothesis that was rejected; Grudge was explicitly aimed at debunking.

A temple complex at Tiwanaku in Bolivia, built around AD 536–600, famous for its precisely cut modular andesite blocks. Ancient-astronaut writers call the stonework impossible; archaeologists call it templates, patience, and skill.

The December 1980 sightings by U.S. Air Force personnel from RAF Bentwaters and Woodbridge in Suffolk, England, documented in the Halt memo. Often called Britain's Roswell.

Alleged shape-shifting reptile-humanoid aliens said to control human institutions, a theory associated above all with David Icke since the 1990s. It has no evidentiary basis and overlaps with older conspiracy myths.

A CIA-convened panel of scientists in January 1953, prompted by the 1952 Washington flap, which recommended debunking UFO reports to keep them from clogging military channels. The origin of the belief that the government set out to explain sightings away.

The July 1947 recovery of debris from a ranch near Roswell, New Mexico, announced by the local Army air base as a "flying disc" and retracted as a weather balloon the same day. The Air Force later identified it as a Project Mogul balloon; ufology calls it a crashed craft.

The facility at Papoose Lake, south of Area 51, where Bob Lazar says he worked on alien craft in 1988–89. No public record of it exists.

In abduction accounts, an ordinary memory, often an owl, a deer, or a doctor, that the experiencer later believes was laid over an alien encounter to hide it.

The search for extraterrestrial intelligence: listening for radio or optical signals of technological origin, from Frank Drake's Project Ozma in 1960 to today's Breakthrough Listen. No confirmed signal has ever been found.

UC Berkeley's volunteer computing project, 1999–2020, in which millions of home computers searched Arecibo radio data for signals. It found none and went into hibernation; Breakthrough Listen carries on the search.

The frail grey alien in a set of 2011 YouTube clips presented as leaked KGB footage, and revived in 2026. No source has ever been produced; visual-effects analysts read it as a 3D animation with film-damage effects.

The Navy's huge polyethylene research balloons of the late 1940s, secret at the time, which flew above 60,000 feet and looked like enormous metallic objects. One is the accepted explanation for the object Thomas Mantell died chasing in 1948.

One of four panels of the Spacecraft-Lunar Module Adapter that enclosed the Apollo lunar module and separated from the rocket after launch. Buzz Aldrin identifies a tumbling SLA panel as the object the Apollo 11 crew saw pacing them on the way to the Moon.

A state between sleep and waking in which a person is conscious but cannot move, often with a sense of presence, pressure on the chest, and vivid hallucinations. It is the leading scientific explanation for bedroom-visitor abduction accounts.

The tall, fair, benevolent visitors the contactees of the 1950s said they met, beginning with George Adamski's Venusian "Orthon" in 1952: human-looking, concerned about atomic weapons, and bearing a message of peace. The origin of the Nordic alien type and of a whole devotional movement.

Beings from the sky in the oral traditions of many Indigenous cultures, from Lakota and Hopi accounts to Aboriginal Australian Dreamtime stories. Ancient-astronaut writers read them literally; the cultures themselves frame them in their own cosmologies.

J. Allen Hynek's 1966 explanation for sightings in Michigan, which became a national joke and a byword for official dismissal, and helped push Congress toward the Condon study.

Chalk-white, blue-eyed beings up to nine feet tall that former Air Force weather observer Charles Hall says he met at the Nellis range in the 1960s, described in his Millennial Hospitality books. Known from his account alone.

Any detectable sign of technology, such as a narrow-band radio signal, industrial pollution in an exoplanet's atmosphere, or the waste heat of a megastructure. Modern SETI is the search for technosignatures.

The white, oblong object U.S. Navy pilots including Cmdr. David Fravor encountered off San Diego in November 2004 during USS Nimitz training, captured on the FLIR1 video. The best-documented modern military case.

A supposed secret U.S. triangular anti-gravity aircraft, described since the 1990s and credited with black-triangle sightings. No evidence that it exists has surfaced; the name comes from UFO lore, not any program record.

Moving between air, water and space without apparent change in performance, one of the "five observables" former AATIP head Luis Elizondo listed as characteristic of the most puzzling UAP reports.

Unidentified anomalous phenomena (earlier "unidentified aerial phenomena"), the official U.S. government term since the late 2010s for what the public calls UFOs, broadened in 2022 to cover objects in water and space.

Unidentified flying object, the term the U.S. Air Force adopted in 1953 to replace "flying saucer." It means only that the observer could not identify it; most are eventually explained as aircraft, balloons, satellites, planets, or camera artifacts.

An unacknowledged special access program: a classified program whose very existence is denied to those without a need to know. Whistleblowers such as Grusch and Brown say UAP crash-retrieval efforts are hidden inside them.

The "hollow ship" of an 1803 Japanese account: a round vessel that washed ashore carrying a strange woman and inscriptions nobody could read. Sometimes cited as an early UFO report; historians read it as folklore.

The flying palaces and chariots of Hindu epics such as the Ramayana. Ancient-astronaut writers treat them as descriptions of aircraft; the "Vaimanika Shastra" text often cited as a manual was written in the twentieth century.

A fictional energy from Edward Bulwer-Lytton's 1871 novel "The Coming Race." The "Vril Society" said to have powered Nazi saucers was inflated from a 1947 essay about a trivial occult group; its medium Maria Orsic first appears in 1990s neo-Nazi material.

A current or former insider who reports alleged wrongdoing through protected channels. In the UAP context, someone like David Grusch or Matthew Brown who says the government is concealing what it knows.

March 15, 1953, the date on which the International Flying Saucer Bureau, a Connecticut club run by Albert Bender, asked its members to send a telepathic message to any craft that might be listening. The message's opening words became the title of Klaatu's 1976 song "Calling Occupants of Interplanetary Craft," a hit for the Carpenters in 1977; Bender closed the Bureau months after the experiment, saying three men in black had told him to.

A strong, narrow-band radio signal near the hydrogen line recorded by the Big Ear telescope on August 15, 1977 and never detected again. Astronomer Jerry Ehman wrote "Wow!" beside it on the printout.

The creature of the Alien films: a biomechanical parasite with a life cycle of egg, facehugger, chestburster and adult, acid for blood and a second jaw inside its mouth. The word, Greek for "strange form," was a generic military term in Aliens (1986) that fans adopted as the species name.

A binary star system about 39 light-years away, named as the Greys' home after Marjorie Fish matched Betty Hill's star map to it in the 1970s. Bob Lazar later said the craft at S-4 came from there.

John Ball's 1973 answer to the Fermi paradox: advanced civilizations know about us and deliberately leave us alone to develop, as visitors observe animals in a zoo. Unfalsifiable, but popular.