The Collaborative International Dictionary of English v.0.48:

Shoshones \Sho*sho"nes\, n. pl.; sing. Shoshone. (Ethnol.)
   A linguistic family or stock of North American Indians,
   comprising many tribes, which extends from Montana and Idaho
   into Mexico. In a restricted sense the name is applied
   especially to the Snakes, the most northern of the tribes.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Shoshone
    n 1: a member of the North American Indian people (related to
         the Aztecs) of the southwestern United States [syn:
         Shoshone, Shoshoni]
    2: the language spoken by the Shoshone (belonging to the Uto-
       Aztecan family)