ARK may refer to:

• Absolute Return for Kids, charity
• Netherlands Court of Audit (Algemene Rekenkamer)
• Ararat International Airlines, ICAO airline designator
• Archaeological Recording Kit, a database and GIS web-based recording system for archaeology
• Archival Resource Key, persistent identifier given to information objects of any type
• Arkadelphia (Amtrak station), Amtrak station code ARK
• Armoured Ramp Carrier, a specialist armoured vehicle
• IATA airport code for Arusha Airport
• Autonomous Region of Krajina, or Serbian Autonomous Oblast of Bosanska Krajina, was a Serbian autonomous region in Bosnia and Herzegovina
• Northern Ireland Social and Political Archive in collaboration with Queens University Belfast and the University of Ulster
• Space Colony ARK, a fictional space station in the Sonic the Hedgehog series of video games
• ARK Music Factory, a musical composition and production company based in Los Angeles, California
• ARK Theatre Company, an actor-driven repertory theatre ensemble working in Los Angeles, California
• , An early access open world survival game

Ark may refer to:

• Ark (Bangladeshi band), a Bangladeshi rock band
• Ark (Norwegian band), a progressive metal band
• Ark (British band), a melodic rock band
• The Ark (Swedish band), Swedish glam-rock band
• The Ark (South Korean band), a South Korean girl group

ARC is a lossless data compression and archival format by System Enhancement Associates (SEA). It was very popular during the early days of networked dial-up BBS. The file format and the program were both called ARC. The ARC program made obsolete the previous use of a combination of the SQ program to compress files and the LU program to create .LBR archives, by combining both compression and archiving functions into a single program. Unlike ZIP, ARC is incapable of compressing entire directory trees. The format was subject to controversy in the 1980s—an important event in debates over what would later be known as open formats.

Arkansas is a state located in the Southern region of the United States. Its name is of Siouan derivation, denoting the Quapaw Indians. The state's diverse geography ranges from the mountainous regions of the Ozark and the Ouachita Mountains, which make up the U.S. Interior Highlands, to the densely forested land in the south known as the Arkansas Timberlands, to the eastern lowlands along the Mississippi River and the Arkansas Delta. Known as "the Natural State", Arkansas has many diverse regions that offer residents and tourists a variety of opportunities for outdoor recreation.