Synonyms: taxonomies, classification, systematization, categorizing, sorting
Taxonomies are systems used to name, describe, classify and organize things.
The first thing to remember about taxonomies is that there is never one correct taxonomy per set of elements. Taxonomy is not so much about the products, it is more about the users. Each user has his own "correct" taxonomy, or more properly, each combination of a user and task he has to achieve will have its own correct taxonomy.