n. pl. cat·e·go·ries
1. A specifically defined division in a system of classification; a class.
2. A general class of ideas, terms, or things that mark divisions or coordinations within a conceptual scheme, especially:
a. Aristotle's modes of objective being, such as quality, quantity, or relation, that are inherent in all things.
b. Kant's modes of subjective understanding, such as singularity, universality, or particularity, that organize perceptions into knowledge.
c. A basic logical type of philosophical conception in post-Kantian philosophy.
a. A property or structural unit of a language, such as a part of speech or a type of phrase.
b. A specific grammatical defining property of a linguistic unit or class, such as number or gender in the noun and tense or voice in the verb.
4. Mathematics A class of objects, together with a class of morphisms between those objects, and an associative composition rule for those morphisms. Categories are used to study a wide variety of mathematical constructions in a similar way.
[French catégorie, from Old French, from Late Latin catēgoria, class of predicables, from Greek katēgoriā, accusation, charge, from katēgorein, to accuse, predicate : kat-, kata-, down, against; see CATA- + agoreuein, ēgor-, to speak in public (from agorā, marketplace, assembly; see ger- in the Appendix of Indo-European roots).]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.