'arbalest' originates from Old French, specifically the word 'arbaleste', which in turn reflects Medieval Latin 'arcuballista' (from Latin 'arcus' meaning 'bow' and 'ballista' meaning 'missile-throwing engine').

'arbalest' changed from Medieval Latin 'arcuballista' into Old French 'arbaleste' and then entered Middle English as 'arbalest', eventually becoming the modern English word 'arbalest'.

Initially it referred broadly to a missile-throwing engine or bow-like war engine ('arcuballista'), but over time the meaning narrowed to denote the handheld or portable large crossbow used in medieval warfare ('arbalest').