Arch Rivals is a basketball arcade game released by Midway in 1989. Billed by Midway as "A Basket Brawl", the game features two-on-two full court basketball games in which players are encouraged to punch opposing players and steal the ball from them. Arch Rivals allows players to select from a variety of fictional teams (although arcade operators can change the team names to reflect real ones) and players. One playable character, "Tyrone" was also featured in the animated Power Team segments of the television series Video Power. Home versions of the game were released for the Nintendo Entertainment System, the Sega Genesis/Mega Drive as well as the Game Gear. Emulated versions of the game were included in the compilations Midway Arcade Treasures 2, Midway Arcade Treasures Deluxe Edition, and Midway Arcade Origins. The game has been considered a forerunner to Midway's popular arcade basketball game, NBA Jam.

Archon: The Light and the Dark is a 1983 video game developed by Free Fall Associates and one of the first five games published by Electronic Arts. It's similar in concept to Chess, except that landing on another player's piece results in an arcade-style fight to determine the victor.Archon was originally developed for Atari 8-bit computers, then ported to the Apple II, Commodore 64, Amstrad CPC, ZX Spectrum, Amiga, IBM PC, Apple Macintosh, PC-88, and NES. It was designed by Paul Reiche III (who also created the graphics for the game) and Jon Freeman, and programmed by Anne Westfall.A sequel was released in 1984: Archon II: Adept.

The Arctic (/ˈɑrktɪk/ or /ˈɑrtɪk/) is a polar region located at the northernmost part of the Earth. The Arctic consists of the Arctic Ocean and parts of Canada, Russia, the United States (Alaska), Denmark (Greenland), Norway, Sweden, Finland, and Iceland. The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost. The area can be defined as north of the Arctic Circle (66° 33'N), the approximate limit of the midnight sun and the polar night. Alternatively, it can be defined as the region where the average temperature for the warmest month (July) is below 10 °C (50 °F); the northernmost tree line roughly follows the isotherm at the boundary of this region. Socially and politically, the Arctic region includes the northern territories of the eight Arctic states, although by natural science definitions much of this territory is considered subarctic. The Arctic region is a unique area among Earth's ecosystems. The cultures in the region and the Arctic indigenous peoples have adapted to its cold and extreme conditions. In recent years the extent of the sea ice has declined. Life in the Arctic includes organisms living in the ice, zooplankton and phytoplankton, fish and marine mammals, birds, land animals, plants and human societies.

Arkanoid (アルカノイド, Arukanoido?) is an arcade game developed by Taito in 1986. It expanded upon Atari's Breakout games of the 1970s by adding power-ups, different types of bricks, and a variety of level layouts. The title refers to a doomed "mothership" from which the player's ship, the Vaus, escapes.

Arkanoid (アルカノイド, Arukanoido) is an arcade game developed by Taito in 1986. It expanded upon Atari's Breakout games of the 1970s by adding power-ups, different types of bricks, and a variety of level layouts. The title refers to a doomed "mothership" from which the player's ship, the Vaus, escapes.

Arkista's Ring is a video game developed and published by American Sammy for the Nintendo Entertainment System in 1990. A prime example of the action-adventure genre, the game is set in a fantasy world, and the player controls a female elf named Christine, in her quest to find the Elven ring of Arkista. It is considered to be a rare NES title.

Armadillos are New World placental mammals with a leathery armor shell. The Dasypodidae are the only surviving family in the order Cingulata, part of the superorder Xenarthra, along with the anteaters and sloths. The word armadillo means "little armored one" in Spanish. The Aztecs called them āyōtōchtli [aːjoːˈtoːt͡ʃt͡ɬi], Nahuatl for “turtle-rabbit”: āyōtl [ˈaːjoːt͡ɬ] (turtle) and tōchtli [ˈtoːt͡ʃt͡ɬi] (rabbit). About 10 extant genera and 20 extant species of armadillo have been described, some of which are distinguished by the number of bands on their armor. Their average length is about 75 cm (30 in), including tail. The giant armadillo grows up to 150 cm (59 in) and weighs up to 59 kg (130 lb), while the pink fairy armadillo is a diminutive species, with an overall length of 12 to 15 cm (5 to 6 in). All species are native to the Americas, where they inhabit a variety of environments. Like all other xenarthran lineages, armadillos originated in South America. Due to the continent's former isolation, they were confined there for most of the Cenozoic. The recent formation of the Isthmus of Panama allowed a few members of the family to migrate northward into southern North America by the early Pleistocene, as part of the Great American Interchange. (Some of their much larger cingulate relatives, the pampatheres and glyptodonts, made the same journey.) Today, all extant armadillos species are still present in South America. They are particularly diverse in Paraguay (where eleven species exist) and surrounding areas. Many species are endangered. Some, including four species of Dasypus, are widely distributed over the Americas, whereas others, such as Yepes's mulita, are restricted to small ranges. Two species, the northern naked-tailed armadillo and nine-banded armadillo, are found in Central America; the latter has also reached the United States, primarily in the south-central states (notably Texas), but with a range that extends as far east as South Carolina and Florida, and as far north as Nebraska and central Indiana. Their range has consistently expanded in North America over the last century due to a lack of natural predators.

Artelius (アルテリオス) is a Nintendo Family Computer action role-playing video game that was released exclusively in Japan on November 13, 1987.

Asmik-kun Land (アスミッくん ランド Asumikkun Rando') is a Famicom game published by Asmik in 1991. A pink dinosaur named Asmik-kun (named "Boomer" in the English release of Boomer's Adventure in ASMIK World) seeks to recover six fragments so he can wake the dragon ruler of the world and make Asmik Land a paradise.