ArapahoPronunciation: /əˈrapəhəʊ/Definition of Arapaho noun (plural same or Arapahos) 1a member of a North American Indian people living chiefly on the Great Plains, especially in Wyoming. 2 [mass noun] the Algonquian language of the Arapaho, now almost extinct. adjective relating to the Arapaho or their language. Origin:from Crow alappahó, literally 'many tattoo marks'Arapaho in other Oxford dictionaries Definition of Arapaho in the US English dictionary