A Gundam is an advanced, high performance mobile suit, often constructed to be much more powerful than the standard production mobile suits. They are generally equipped with the latest experimental technology available at the time of their construction. The definition of a Gundam varies from one timeline to another. In most series it is used as an acronym to refer to something, however in all but the most recent series these acronyms were derived after the fact and do not appear at any point in the animated works. The protagonist's mobile suit of a series usually carries the name Gundam. The main suit in each series usually sports a mainly white and blue color scheme, with yellow and red accents, and sports at least one pair of yellow or white V-fins on its head.
In the Universal Century, Gundams are usually equipped with powerful beam weapons and are typically armored in a special alloy, Luna Titanium (later renamed Gundarium in honor of the famous mobile suit). However, the use of Gundarium in the construction of standard mobile suits became widespread. The use of other alloys to manufacture later Gundam models, such as the RX-178 Gundam Mk-II, further blurred the distinction of a Gundam in this era.
In this era GUNDAM stands for ""General purpose Utility Non-Discontinuity Augmentation Maneuvering weapon system". In canon this acronym was not derived until after the One Year War. This term was derived after the production of Mobile Suit Gundam.
In the Future Century, the term "Gundam" denotes the mobile fighters created specifically for use in the Gundam Fight tournament proposed by Professor E.C. Ducer. The name of the mobile fighters is derived from the lightweight and ultra-tough Gundarium alloy used in their construction. These mobile fighters are controlled by their pilots via the Mobile Trace System.
In this era GUNDAM refers either to "Gamma UNificational Dimalium Amalgam Mobile-suit" and the more relevant "Govern of Universe Nation Decide Advanced Mobile-suit".
In the After Colony alternate universe, Gundams are loosely defined as mobile suits that are made using Gundarium θ, or as it is more commonly known in this timeline, Gundanium. However, there are mobile suits that are made from Gundanium but are not called "Gundams", such as Vayeate and Mercurius.
In After Colony the GUNDAM acronym is defined as "Genetic on Universal Neutraly Different Alloy-nium Mobile suit".
In the After War timeline, Gundams are advanced high-performance mobile suits first designed and built by the United Nations Earth near the end of the 7th Space War against the Space Revolutionary Army, and later used by Vulture and the New United Nations Earth forces in the 8th Space War. The origin of the term in this timeline is unknown, it and ∀ Gundam are the only series in which it does not have an acronym.
Only one Gundam is seen in this timeline, the SYSTEM ∀-99 (WD-M01) ∀ Gundam. The origin of the term can be assumed to be related to one (or several) of the other Gundam series that are referenced in Turn A as being part of the Dark History. Like Gundam X, in this series the word "Gundam" has no specific acronym.
In the Cosmic Era, the term "Gundam" refers to the prototype mobile suits that require powerful mobile suit operation system (M.O.S) to function. The nickname of Gundam was coined by Kira Yamato to Strike Gundam when he read the acronym of the M.O.S., General Unilateral Neuro-link Dispersive Autonomic Maneuver system, or the G.U.N.D.A.M. acronym in and of itself. The crew of the Archangel then slowly caught on to the term and subsequent prototype mobile suits from all major factions have hence been referred to as Gundams. However, the official name for Gundams in the Cosmic Era is "G-Weapon".
In the Cosmic Era all of the many Gundam acronyms refer to the name of the OS on their respective mobile suits. The acronyms are as follows:
- "General Unilateral Neuro-link Dispersive Autonomic Maneuver synthesis system" is Morgenroete's designation for the OS mounted on the "Project G" MS. This includes the GAT-X105 Strike, GAT-X102 Duel, GAT-X103 Buster, and GAT-X207 Blitz, GAT-X303 Aegis, MBF-02 Strike Rouge and later the ORB-01 Akatsuki.
- "Generation Unsubdued Nuclear Drive Assault Module complex" is the term used by ZAFT to refer to the Gundams they designed using the technology acquired from the stolen Morgenroete machines. The machines using this OS are the ZGMF-X09A Justice, ZGMF-X10A Freedom Gundam (as well as their latter incarnations, the ZGMF-X20A Strike Freedom and ZGMF-X19A ∞ Justice, as well as the ZGMF-X13A Providence).
- The similar term, "Generation Unrestricted Network Drive Assault Module", was the designation for most of the Second Stage Series of Gundams including the ZGMF-X56S Impulse, ZGMF-X24S Chaos, ZGMF-X31S Abyss, ZGMF-X88S Gaia and the ZGMF-X23S Saviour.
- "Gigantic Unilateral Numerous Dominating AMmunition" is an acronym unique to the Earth Alliance's GFAS-X1 Destroy.
- Specifically the ZGMF-X666S Legend and ZGMF-X42S Destiny of the ZAFT Second Stage Series use the acronym "GUNNERY UNITED NUCLEAR-DUETERION ADVANCED MANEUVER SYSTEM".
- The last of the many Cosmic Era Gundam acronyms is "Guider UNmanned Deployment Autonomic Manipulation", this acronym is another unique one, it refers only to the GSX-401FW Stargazer.
In the Anno Domini timeline, Gundams are generally mobile suits constructed and used by the private paramilitary organization Celestial Being although they are a few exceptions. Unlike other mobile suits in the timeline, the Gundams are powered by a semi-perpetual generator unit known as the GN Drive, allowing them to operate for an indefinite period of time. The GN Drive produces GN Particles that have a myriad of uses, including energy generation, propulsion, usage in weaponry (both offensive and defensive), weight and mass manipulation, radar disruption, etc. These particles and the various systems that use them also play a role in the Gundams' superior performance over conventional mobile suit. Additionally, the Gundams can function in multiple environment including land, air, space and underwater without any modifications.
Setsuna F. Seiei is known to take this definition a step further, labelling anything which assists in the eradication of conflict as a Gundam regardless of whether it is a machine or a human being.
In Anno Domini, "G.U.N.D.A.M." is lettered as such, however it is not explained as an acronym. The term "Gundam" was coined as early as Aeolia Schenberg's time and was used by him in the recording where he introduced Celestial Being. Despite being historically credited as the creator of mobile suits, Aeolia himself did not expect the Gundams to be humanoid weapons.
In the Advanced Generation, the Gundams are primarily high-performance mobile suits designed based on data provided by the AGE System. The term may also refer to the legendary mobile suit, The Gundam, which appeared from the time of the Silver Chalice Treaty as the "savior that ended the war." The first Gundam developed by the AGE System, the AGE-1 Gundam AGE-1 Normal, may have referenced this legendary mobile suit.
In the Post Disaster timeline, "Gundam" refers to a Mobile Suit frame design used in the Calamity War 300 years ago. As such, Gundams in this timeline are also commonly referred to as "Gundam Frames". Gundam Frames are each powered by a pair of Ahab reactors, while other Mobile Suit Frames typically only use one Ahab reactor. Due to the difficulty in keeping both reactors functioning in parallel, only 72 units were produced. During the events of Mobile Suit Gundam IRON-BLOODED ORPHANS, only 26 Gundam Frames are confirmed to still be operational. Each Gundam Frame is named after the numerically corresponding demon listed in the Ars Goetia.