ARC may stand for:

• Aqaba Railway Corporation, a freight railway in Jordan
• ARC Diversified, a non-profit organization that manufactures food products and employs the severely disabled
• ARC/Architectural Resources Cambridge, Inc., an architectural design firm located in Cambridge, Massachusetts
• A&R Channel, American cable television video on demand network based in Los Angeles
• American Record Company (1904–1908), a United States record label
• African Rainforest Conservancy, an environmental nonprofit
• Amalgamated Roadstone Corporation, a British stone quarrying company
• American Record Corporation (1929–1938), a United States record label
• American Reprographics Company, the largest reprographics company in the United States
• Archaeological Review from Cambridge, a non-profit archaeological journal from the University of Cambridge

Arc may refer to:

• Arc (geometry), a segment of a differentiable curve
• Arc (projective geometry), a particular type of set of points of a projective plane
• Arcminute, a measure used for angles, equal to 1/60th of a degree
• "arc-", a prefix sometimes used for an inverse function, specifically trigonometry functions
• A directed edge in graph theory

ARC is a lossless data compression and archival format by System Enhancement Associates (SEA). It was very popular during the early days of networked BBS. The file format and the program were both called ARC. The ARC program essentially made obsolete the use of combinations of the SQ program to compress files and the LU program to create .LBR archives by combining the functions of both compression and archiving into a single program. ARC compresses multiple files into one - but unlike ZIP, not entire directory trees. The .arc format was the subject of quite a bit of controversy in the 1980s - an important event in the open source debate.