'assagais' originates from Portuguese, specifically the word 'azagaia' (also spelled 'azagaya'), which referred to a spear.

'azagaia' entered European languages (Portuguese, then via accounts of Africa into English and French) and appears in Early Modern English as 'assegai' or 'assagai'; the English plural later appears as 'assagais' or 'assegais'.

Initially, it meant 'a type of spear'; over time the core meaning has remained the same, referring generally to the African spear in historical or ethnographic contexts.