'war-band' originates from a modern English compound of 'war' + 'band'; 'war' ultimately comes via Old North French 'werre' (from Frankish *werra) meaning 'confusion, strife', and 'band' comes from Old English/Old Norse 'band' meaning 'that which binds; a group'.

'war-band' developed in Middle English by combining the word for armed conflict ('war') with 'band' (a group or binding), producing phrases like 'war-band' and later the variant spelling 'warband'.

Initially it meant 'a band bound together for warfare or raiding'; over time the basic sense has remained largely the same, referring generally to a small group of combatants.