The Collaborative International Dictionary of English v.0.48:

Inca \In"ca\, n.
   (a) An emperor or monarch of Peru before, or at the time of,
       the Spanish conquest; any member of this royal dynasty,
       reputed to have been descendants of the sun.
   (b) pl. The people governed by the Incas, now represented by
       the Quichua tribe.
       [1913 Webster]

   Inca dove (Zool.), a small dove (Scardafella inca),
      native of Arizona, Lower California, and Mexico.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Inca
    n 1: a ruler of the Incas (or a member of his family)
    2: a member of the Quechuan people living in the Cuzco valley in
       Peru [syn: Inca, Inka, Incan]
    3: the small group of Quechua living in the Cuzco Valley in Peru
       who established hegemony over their neighbors in order to
       create an empire that lasted from about 1100 until the
       Spanish conquest in the early 1530s [syn: Inca, Inka]