That division of the natural sciences which treats of the classification of animals and plants, primarily by consideration of their natural relationships with respect to their structure or genetic origin; the laws or principles of classification; systematics.

A systematic arrangement of objects or concepts showing the relations between them, especially one including a hierarchical arrangement of types in which categories of objects are classified as subtypes of more abstract categories, starting from one or a small number of top categories, and descending to more specific types through an arbitrary number of levels. An ontology usually contains a taxonomy as one of the important principles of organization.

the science of classifying all living things by arranging them in groups according to the relationship of each to the others.

The study of the scientific classi...

a collection of terms arranged in a treelike hierarchy (a directed acyclic graph) to represent groupings, sub-groupings, sub-sub-groupings, and so on

a controlled vocabulary that is designed to populate the NASA metadata core specification

a hierarchy of subject matter from the general to the specific

a set of terms that are arranged into a generalization-specialization hierarchy

a list of things that are similar, yet some are more complex than others

The naming of 'things', not to be confused with name-calling.

The Montague Institue Review calls a taxonomy "a system for naming and organizing things into groups that share similar characteristics." Taxonomies often come to play in content management systems and document management systems. Without a solid taxonomy and structure, all the software in the world isn't going to make managing your content any easier.