The glossary

The Council's reference lexicon.

Every term in the modern UAP discourse, defined with the precision the topic deserves. Cross-linked to cases and other terms.

#A B D F G H I L M N O P R T U

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'Oumuamua

The first confirmed interstellar object, designated 1I/'Oumuamua, discovered in October 2017 by the Pan-STARRS survey. Notable for its elongated shape, lack of cometary activity, and small non-gravitational acceleration.

A

AARO

All-domain Anomaly Resolution Office — the U.S. Department of Defense entity established in 2022 to detect, identify, and attribute unidentified anomalous phenomena across air, sea, space, and transmedium domains.

AATIP

Advanced Aerospace Threat Identification Program — the secretive U.S. Department of Defense unit that ran from 2007 to 2012, studying anomalous aerospace events for potential threat implications.

B

Belgian Wave

The 1989–1990 Belgian UFO sighting wave, featuring thousands of witness reports of large triangular craft and an officially-released military intercept report from the night of 30–31 March 1990.

Bracewell probe

A hypothetical autonomous interstellar probe sent by an extraterrestrial civilization to observe and possibly communicate with technological neighbors. Proposed by physicist Ronald Bracewell in 1960.

D

Drake equation

A 1961 probabilistic framework proposed by astronomer Frank Drake for estimating the number of detectable extraterrestrial civilizations in the Milky Way galaxy. Each term carries large uncertainty; the equation is a structured way of organizing ignorance, not a calculation of contact probability.

F

Fermi paradox

The apparent contradiction between the high estimated probability of extraterrestrial civilizations (per the Drake equation) and the absence of obvious evidence of contact. Named for physicist Enrico Fermi's 1950 lunchroom question: 'Where is everybody?'

FLIR

Forward Looking Infrared — a class of thermal-imaging sensor mounted on military aircraft and other platforms, used to detect heat signatures of objects against background. Many of the most-cited modern UAP videos are FLIR captures.

Foo fighter

World War II Allied aircrew slang for unidentified luminous objects observed accompanying military aircraft, particularly over the European and Pacific theaters in 1944–1945.

G

Ghost rocket

Sweden- and Scandinavia-centered reports of rocket-like flying objects observed in 1946, predating the Arnold sighting and constituting one of the first post-WWII waves of unidentified aerial phenomena.

Gimbal

The 2015 ATFLIR video captured by an F/A-18 from the USS Theodore Roosevelt, showing a smooth oblong object that appears to rotate. The Department of Defense confirmed the footage's authenticity in 2020.

H

Hessdalen lights

Recurring luminous atmospheric phenomena in the Hessdalen Valley of central Norway, observed since the late 1970s and the subject of continuous instrumented monitoring by Project Hessdalen since 1984.

I

Interstellar object

A small body — asteroid, comet, or otherwise — that originates outside our solar system and passes through it on a hyperbolic trajectory. As of 2026, three confirmed interstellar objects have been detected: 1I/'Oumuamua (2017), 2I/Borisov (2019), and 3I/Atlas (2025–2026).

L

Lens flare

An optical artifact produced when bright light scatters within a camera lens, often appearing as geometric shapes, halos, or streaks. The most-common single explanation for purported UFO photographs and videos.

M

MUFON

Mutual UFO Network — the largest civilian UFO investigation organization in the United States, founded in 1969 and operating a structured field-investigator network.

N

NHI

Non-Human Intelligence — a term increasingly used in U.S. government UAP discourse to refer to any intelligence not of human origin, with deliberate breadth (terrestrial-but-non-human, extraterrestrial, interdimensional, etc.).

NUFORC

National UFO Reporting Center — a U.S. civilian sighting-report intake service founded in 1974, operating the most comprehensive public sighting database in North America.

O

ODNI

Office of the Director of National Intelligence — the U.S. cabinet-level office overseeing the 18 components of the Intelligence Community, and the publisher of the 2021 Preliminary Assessment that catalyzed the modern UAP disclosure cycle.

P

Project Blue Book

The U.S. Air Force's primary UFO investigation program from 1952 to 1969, which examined 12,618 reports and concluded that 701 remained 'unidentified' after investigation.

Project Grudge

The second U.S. Air Force UFO investigation program (1949–1951), characterized by an overtly skeptical institutional posture, and the bridge between Project Sign and Project Blue Book.

Project Mogul

A classified U.S. Army Air Forces program (1947–1949) using high-altitude balloon trains to detect Soviet atmospheric nuclear tests via long-range acoustic monitoring. Identified as the source of the 'Roswell incident' debris in the 1994 USAF Roswell Report.

Project Sign

The first U.S. Air Force UFO investigation program, operating from 1948 to early 1949 in response to the post-WWII surge in unidentified aerial sightings.

R

Roswell

The 1947 New Mexico debris-recovery incident that became the foundational story of modern UFO mythology. Officially attributed to a Project Mogul balloon train by USAF reports in 1994 and 1997.

T

Tic Tac

Colloquial name for the oblong, white object reported by USS Nimitz F/A-18 aircrews during the November 2004 encounter off Baja California — and, by extension, the case itself (Council Case #00041).

U

UAP

Unidentified Anomalous Phenomena (formerly Unidentified Aerial Phenomena) — the U.S. government's preferred term for what was historically called UFOs, deliberately broader to include maritime, space, and transmedium objects.

UFO

Unidentified Flying Object — the older, original term for anomalous aerial phenomena, in U.S. government usage from approximately 1952 until replacement by 'UAP' in 2021.