'arbalest' originates from Old French, specifically the word 'arbaleste', where 'ar-' (from Latin 'arcus') meant 'bow' and the rest derived from Late Latin 'ballista' meaning 'missile-thrower'.

'arbalest' changed from Old French 'arbaleste' (Medieval) into Middle English forms such as 'arblast' or 'arbalest', eventually becoming the modern English 'arbalest'. The Old French form itself came via Late Latin 'arcuballista' (literally 'bow-ballista') from Latin 'arcus' (bow) + 'ballista' (engine for throwing missiles).

Initially it referred broadly to mechanical missile-throwing engines or a large bow-like siege engine; over time it narrowed to mean specifically a large handheld crossbow used in medieval Europe.