Source : Webster's Revised Unabridged Dictionary (1913)

Ethnology \Eth*nol"o*gy\n. [Gr. ? nation + -logy.]
   The science which treats of the division of mankind into
   races, their origin, distribution, and relations, and the
   peculiarities which characterize them.

Source : WordNet®

ethnology
     n : the branch of anthropology that deals with the division of
         humankind into races and with their origins and
         distribution and distinctive characteristics