'arapaho' originates from the Arapaho language, specifically the autonym 'Hinono'eiinii' (often shortened in English-language sources), where the element 'Hinono'ei' meant 'our people'.

'arapaho' was recorded by early European explorers and traders in forms such as French 'Arapahoe' and later adapted into English as 'Arapaho' (plural 'Arapahos').

Initially it meant 'our people' in the Arapaho language; over time English speakers used the term to refer to an individual member ('Arapaho') or the group collectively ('Arapahos' / 'the Arapaho').