1. (n.) 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. (n.) A treatise on this science.

aerobiology agrobiology anatomy astrobiology bacteriology biochemics biochemistry biochemy bioecology biological science biology biometrics biometry bionics bionomics biophysics botany cell physiology cryobiology cybernetics cytology ecology electrobiology embryology enzymology ethnobiology exobiology genetics gnotobiotics life science microbiology molecular biology pharmacology physiology radiobiology taxonomy virology xenobiology