AI: Artificial Intelligence.

Ames: The name is in reference to Agent Aldrich Ames, the highest-ranking CIA official ever arrested. Ames had been selling US secrets to the Soviet Union.

Arsenal Gear: The newest model of Metal Gear, controlled by GW in order to further the goals of the Patriots.

Battery Park: A park in the southern area of Manhattan in New York.

Big Shell: Designed to represent an offshore cleanup facility built after the Tanker incident of 2007, it is actually camouflage used to disguise Arsenal Gear.

Black Case: A specially-outfitted, black-colored briefcase used by the President of the United States to authorize the use of nuclear weapons. It is carried by one of the rotating Presidential Aides (one from each of the five service branches) and kept within ready access of the President at all times.

Chrysler building: A skyscraper in Manhattan. It was the world's tallest building before the completion of the Empire State Building.

CIA: Central Intelligence Agency, a US espionage and covert operations agency.

Civil War: A war in which participants are within the same ethnicity, or distribution of wealth.

CO: Commanding Officer.

Compton Effect: The total disruption of electronic equipment caused by EMMA pulse.

CP: Command Post.

Crazy Ivan: An alias referring to Revolver Ocelot.

Cypher: An aerial surveillance camera.

Dead Cell: A former Special Forces unit. The only remaining members are Solidus Snake, Vamp, Fortune and Fatman.  The name was originally intended to reflect its anti-terrorist functions.

Delta Force: A Special Operations force of the United States Army Special Operations Command. The force's main task is counter-terrorism.

DIA: Defence Intelligence Agency, a major producer and manager of intelligence for the United States Department of Defence.

Discovery: A reference to the space vessel in "2001: A Space Odyssey."

Empire State Building: A skyscraper in Manhattan. It is, at present, the tallest building in the world, although it had previously been outdone by the World Trade Centre before its destruction in 2001 during the September 11 attacks.

EOD: Explosive Ordnance Disposal, the detection, identification, on-site evaluation, rendering safe, recovery, and final disposal of unexploded explosive ordnance.

FBI: Federal Bureau of Investigation, the principal investigative unit of the US Department of Justice.

Federal Hall: The first capital building of the United States. The original structure was built as New York's City Hall, although it has since been replaced with a museum that commemorates the earlier structure. George Washington became the first President of the United States there on April 30, 1789.

Football: Another name for the Black Case. Contains the "key"™ to activating Arsenal Gear.

Force XXI: A series of Advanced War fighting Exercises in 1997 to test Force XXI concepts, technology, and tactics.

George Washington Bridge: One of the longest suspension bridges in the world, stretching across the Hudson River. It is named after the first President of the United States.

GW: An AI that controls Arsenal Gear and the Metal Gear RAY's that protect it. Created by Emma Emmerich, it is the Patriots' data processing system for controlling the digital flow of information.

Harrier 2: A family of second generation vertical/short take off and landing jet aircraft of the late 20th century. Developed from the earlier Harriers, they are used for light attack or multi-role tasks, and are almost all operated from small aircraft carriers.

Hudson River: A river rising in the mountains of northeast New York and flowing about 507 km southward to Upper New York Bay at New York City. It is named after Henry Hudson, who explored it in 1609, although the first person to see it was Giovanni da Verrazano in 1524.

ICC: Interstate Commerce Commission, the first independent regulatory agency created by the federal government. It was responsible for the regulation of interstate surface transportation between 1887 and 1995.

Ion Mobility Spectrometer: A spectrometer capable of detection and identification of very low concentrations of chemicals.

Iroquois: The name has a double meaning. The Iroquois were a confederacy of Native American tribes headquartered in New York. It was also a Huron word meaning "Black Snake."

IR goggles: Infrared goggles that allow the wearer to see heat sources.

Pliskin: A reference to Snake Pliskin, a character from the movie "Escape from New York."

Jack the Ripper: A reference to the unknown killer who terrorized London between August and November of 1888.

Kamov KA-60 Kasatka: A Russian army helicopter that first flew in 1998.The Russian name "Kasatka" means "killer whale."

King Kong: A well-known American movie about a giant ape that is captured and imported to New York City for exhibition.

La-li-lu-le-lo: An alternative name for the Patriots.

Marine Corps: A branch of the US armed forces composed chiefly of amphibious troops under the authority of the Secretary of the Navy.

Metal Gear RAY: A type of Metal Gear that was originally designed by the Marine Corps to take out other Metal Gears. The new version was reprogrammed to protect Arsenal Gear. The code name comes from a Japanese war plane during World War Two.

Mr. X: The alias used by Olga Gurlukovich, who was an anonymous Cyborg Ninja dedicated to helping Raiden complete the mission.

NAVSCOLEOD Indian Head: Naval School, Explosive Ordnance Disposal. It was the sole Joint Service EOD School in the US from 1955 to 1985.

Navy SEAL: United States Navy Sea, Air and Land Forces. The most elite special operations and counter-terrorist force of the US Navy.

NGO: Nongovernmental Organization.

NMD: National Missile Defence, a military strategy that involves shielding the US against incoming missiles by shooting them down as they approach the country.

NSA: National Security Agency, an agency responsible for encoding and decoding communications intelligence and protecting US signals and information systems.

NSDD: National Security Decision Directive, a form of presidential directive covering national security policy signed by the President.

NYPD: New York Police Department, the largest police force in the United States.

OS: Operating System.

P2P: Peer to peer (user to user), a network that relies on the computing power and bandwidth of the participants in the network rather than concentrating it in a relatively low number of servers.

Patriots: A group of twelve men that are the true holders of power in the United States, above even the President.

Pentagon: The headquarters of the US Department of Defence.

Philanthropy: A group formed by Snake and Otacon, whose main objective is to prevent Metal Gear proliferation.

R&D: Research and Development.

Raiden: The code name comes from the Japanese navy's name for one of its interceptors during World War Two. The US used the code name "Jack" for the same plane.

S3 Plan: Selection for Societal Sanity, a program designed by the Patriots to control and direct all thought in the world. The Plan was falsely believed to be "Solid Snake Simulation," designed to create soldiers on par with Solid Snake" by putting them in an actual situation which is very similar to Shadow Moses.

Second Fleet: A group of US Navy ships responsible for training the Atlantic battle fleet in war-fighting skills and developing new naval tactics.

Secret Service: A branch of the US Treasury Department concerned especially with protection of the President.

Semper Fi: Short for Semper Fidelis, it is Latin for "always faithful." It is the current motto of the US Marine Corps.

Semtex: A general-purpose plastic explosive. It was popular with terrorists because it was, until recently, extremely difficult to detect, easily obtained, and so powerful that as little as 250g could down an airliner.

Skull suit: A new sneaking suit developed by FOXHOUND. Also referred to as "Smart Skin."

Skyscraper Museum: A museum located in New York City, which focuses on high-rise buildings.

Small Boy Unit: A unit that Raiden commanded during the civil war when he was just ten years old. As the name suggests, the unit consisted of only very young male soldiers.

Sons of Liberty: The name that the terrorist group that took over the Big Shell has given itself, as their main objective was to gain freedom from the Patriots. The term "son of liberty" has been used since the 1700's to designate any supporter of freedom.

SOP: Standard Operating Procedure.

Space Defence: All defensive measures designed to destroy attacking enemy vehicles, including missiles, while in space, or to reduce the effectiveness of such an attack.

Special Air Service (SAS): The principal Special Forces organization of the British Army.

US Army: The branch of the United States armed forces that have primary responsibility for land-based military operations.

Verrazano Bridge: The longest suspension bridge in the US, located at the entrance to the New York Harbour. It was named after Giovanni da Verrazano, the first person to see the Hudson River.

VR Training: Virtual Reality training, designed to simulate the events of a real mission as accurately as possible.

White Devil: A reference to the story of an unsolved murder in Italy.

Who Dares Wins: A motto of the British SAS, representing the importance of courage, resourcefulness and the willingness to try new ways of successfully accomplishing missions that are thought to be impossible.

Wisemen's Committee: Another name for the Patriots.

Y2K: A defect in the code of a computer program caused when a year is represented by its last two digits only and the program interprets that year as falling inclusively between 1900 and 1999 instead of between 2000 and 2099. Also called the "millennium bug."