kategorio

Kategorio is a noun in Esperanto meaning a class or grouping of items that share a defining property or criterion. It is used across everyday language, science, and information systems to designate both informal classifications and more formal organizational structures.

Etymology and form: The word is formed with the root categor- plus the common Esperanto suffix -io, used for abstract or collective nouns. Its international origin is reflected in cognates such as category in English and catégorie in French, all tracing back to Greek katégoria via Latin. The plural is kategorioj.

Usage: Kategorioj are employed to organize material in libraries, museums, databases, and websites, supporting navigation, tagging, and search. In education, media, and commerce, they help separate content or products into distinct groups like kulturaj kategorioj or temaj kategorioj, clarifying scope and relationships.

Mathematics: In the field of category theory, kategorio denotes a category—an abstract structure consisting of objects and morphisms with composition and identity laws. This branch, called teorio de kategorioj in Esperanto, uses terms such as morfismoj (morphisms) and funktoj (functors) to describe structure-preserving maps between categories.