1670s, from Anglo-French arsoun (late 13c.), Old French arsion, from Late Latin arsionem (nominative arsio) "a burning," noun of action from past participle stem of Latin ardere "to burn," from PIE root *as- "to burn, glow" (see ash, n.1). The Old English term was bærnet, literally "burning;" and Coke has indictment of burning (1640).