Source : Webster's Revised Unabridged Dictionary (1913)

Zoology \Zo*["o]l"o*gy\, n.; pl. {Zo["o]logies}. [Zo["o]- +
   -logy: cf. F. zoologie. See {Zodiac}.]
   1. That part of biology which relates to the animal kingdom,
      including the structure, embryology, evolution,
      classification, habits, and distribution of all animals,
      both living and extinct.

   2. A treatise on this science.