'armourbearer' originates from Modern English, specifically the compound of 'armour' + 'bearer', where 'armour' came via Old French 'armure' from Latin 'armatura' meaning 'equipment, armor', and 'bearer' comes from Old English 'beran' meaning 'to carry'.

'armour' descended from Latin 'armatura' → Old French 'armure' → Middle English 'armour'; 'bearer' descended from Old English forms of the verb 'beran' ('to bear, carry'), and the compound 'armourbearer' developed in Early Modern English as a literal compound and later retained in biblical and ceremonial usage.

Initially it meant 'one who literally carries armour or weapons'; over time it has preserved that literal sense but also acquired a figurative sense of 'close attendant or supporter,' and in modern usage it is relatively rare and often literary or biblical.