Source : Webster's Revised Unabridged Dictionary (1913)

Onondagas \On`on*da"gas\, n. pl.; sing. {Onondaga}. (Ethnol.)
   A tribe of Indians formerly inhabiting what is now a part of
   the State of New York. They were the central or head tribe of
   the Five Nations.

Source : WordNet®

Onondaga
     n 1: a member of the Iroquoian people formerly living between
          Lake Champlain and the Saint Lawrence River
     2: the Iroquoian language spoken by the Onondaga people