taxonomy

Definitions:

The laws of classification as applied to Natural History.
- A dictionary of scientific terms. By Henderson, I. F.; Henderson, W. D. Published 1920. (noun) (n.) (noun)
The classification of animals and plants; a branch of biology.
- The Winston Simplified Dictionary. By William Dodge Lewis, Edgar Arthur Singer. Published 1919. (noun) (n.) (noun)
That department of natural history which treats of the laws and principles of classification; classification.
- Nuttall's Standard dictionary of the English language. By Nuttall, P.Austin. Published 1914. (noun) (n.) (noun)

Usage examples:

In the nineteenth century the freshwater polyp became a favourite object of biological observation and was watched and examined by a host of observers, among the more noteworthy of whom were Kleinenberg, Nussbaum, and Brauer, who has since the beginning of the present century made an important contribution to the taxonomy of the genus.
- Freshwater Sponges, Hydroids & Polyzoa by Nelson Annandale
The morphological phenomena which find their application in taxonomy belong exclusively to phylogeny.
- A Mechanico-Physiological Theory of Organic Evolution by Carl Von Nägeli
" Taxonomy does not appear to me so dreadful a word as it does to Veblen.
- The Value of Money by Benjamin M. Anderson, Jr.