NOUN (3)

1. a member of the North American Indian people of Arizona and adjacent Mexico and California;

2. a town in southwestern Arizona on the Colorado River and the California border;

3. the Yuman language spoken by the Yuma;

The Collaborative International Dictionary of English v.0.48:

Yumas \Yu"mas\, n. pl.; sing. Yuma. (Ethnol.)
   A tribe of Indians native of Arizona and the adjacent parts
   of Mexico and California. They are agricultural, and
   cultivate corn, wheat, barley, melons, etc.
   [1913 Webster]

   Note: The a wider sense, the term sometimes includes the
         Mohaves and other allied tribes.
         [1913 Webster]

WordNet (r) 3.0 (2006):

Yuma
    n 1: a member of the North American Indian people of Arizona and
         adjacent Mexico and California
    2: a town in southwestern Arizona on the Colorado River and the
       California border
    3: the Yuman language spoken by the Yuma