Arx

Arx, ARX, or ArX may refer to:


 * ARX (Algorithmic Research Ltd.), a digital security company
 * ARX (gene), Aristaless related homeobox
 * ARX (operating system), an operating system
 * Arx (Roman), a Roman citadel, and in particular:
 * The northern hump of the two forming the Capitoline Hill of ancient Rome
 * Arx, Landes, a commune of the Landes département in France
 * Arx Fatalis, a first person role-playing game developed by Arkane Studios in 2002
 * Arx, a sculpture by Lars Vilks
 * Americas Rallycross Championship, also known as ARX Rallycross
 * Add-Rotate-XOR; see block cipher
 * Josef Adolph von Arx (1922-1988), mycologist from the Netherlands