Source : Webster's Revised Unabridged Dictionary (1913)

Ethology \E*thol"o*gy\, n. [Gr. ? a depicting of character; ?
   custom, moral nature + ? to speak.]
   1. A treatise on morality; ethics.

   2. The science of the formation of character, national and
      collective as well as individual. --J. S. Mill.

Source : WordNet®

ethology
     n : the branch of zoology that studies the behavior of animals
         in their natural habitats