- The branch of biology that deals with animals and animal life, including the study of the structure, physiology, development, and classification of animals.
- The animal life of a particular area or period.
- The characteristics of a particular animal group or category.
- A book or scholarly work on zoology.
- that part of <xref>biology</xref> which relates to the <xref>animal</xref> kingdom, including the structure, <xref>embryology</xref>, <xref>evolution</xref>, <xref>classification</xref>, habits, and distribution of all animals, both living and <xref>extinct</xref>.
- a treatise on this science.