What does category mean?
A category is a class or grouping that brings together people, objects, ideas, or events which share some defining characteristic. Sorting the world into categories is one of the most basic operations of thought: shops arrange goods by category, competitions award prizes by category, and scientists classify species into ever-finer ones. The word carries no particular connotation — it is neutral and register-flexible, appearing everywhere from casual conversation ('what category would you put this film in?') to formal scholarship. Its deepest sense comes from philosophy: Aristotle used 'category' to name the ten most fundamental kinds of being — substance, quantity, quality, relation, and so on — and later thinkers from Kant onward have debated what our most basic categories of understanding might be. From it we derive familiar verbs like 'categorize' and adjectives like 'categorical', meaning unconditional or absolute. Few words so quietly structure how we think.
nounA class or division of people or things sharing one or more common characteristics; in philosophy, one of the most general classes into which entities of thought or experience are divided.
- A class or group into which people or things are sorted because they share characteristics.
- In philosophy (especially since Aristotle), one of the most fundamental classes into which all beings or concepts can be divided.
"The store sorts its books into categories such as fiction, history, and self-help."
"Applicants are judged within their own age category."
"Kant argued that space and time are categories of human understanding rather than properties of things in themselves."
Standard regular plural; note the spelling change of y to -ies.
"The website organizes its archive into several categories by difficulty level."
The word 'category' was invented by Aristotle over two thousand years ago — he used it to name the ten ultimate kinds of everything that exists.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of category
Category comes from the Greek katēgoria, meaning 'accusation' or 'predication', derived from katēgorein ('to assert' or 'to accuse'), itself built on kata- ('against') and agoreuein ('to speak in the assembly'). Aristotle gave it its enduring philosophical sense as a fundamental kind of predication or being, in his work the Categories. English adopted the word in the late sixteenth century, initially in its logical and philosophical sense, before it broadened over subsequent centuries into the everyday notion of any class or sorting-group. Related words sharing Greek roots include catastrophe (kata- + strophē, 'turning') and catalogue (kata- + legein, 'to gather').
Related word forms
How category is actually used
Register-neutral: equally at home in everyday speech, commerce, law, and academic philosophy. In technical contexts (taxonomy, data science, linguistics) it often implies a formally defined class. The plural is 'categories'.
Easily confused with category
Category is the neutral term for any class of things, while a 'category mistake' names the specific philosophical and informal error of assigning something to a class to which it does not belong.