category

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A specifically defined division in a system of classification; a class.
2. n. A general class of ideas, terms, or things that mark divisions or coordinations within a conceptual scheme, especially:
3. n. Aristotle's modes of objective being, such as quality, quantity, or relation, that are inherent in everything.
4. n. Kant's modes of subjective understanding, such as singularity, universality, or particularity, that organize perceptions into knowledge.
5. n. A basic logical type of philosophical conception in post-Kantian philosophy.
6. n. Linguistics A classificatory structural unit or property of a language, such as a part of speech, verb phrase, or object.
7. n. Linguistics 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.

Century Dictionary and Cyclopedia

1. n. In logic, a highest notion, especially one derived from the logical analysis of the forms of proposition. The word was introduced by Aristotle, who applies it to his ten predicaments, things said, or summa genera, viz., substance, quantity, quality, relation, action, passion, where, when, posture or relative position of parts, habit or state. These are derived from such an analysis of the proposition as could be made before the developed study of grammar. The categories or highest intellectual concepts of Kant are: categories of quantity — unity, plurality, totality;categories of quality —reality, negation, limit between these; categories of relation— substance and accident, cause and effect, action and reaction; categories of modality —possibility, impossibility, actuality, non-actuality, necessity, non-necessity. Modern formal logic furnishes this list: qualities, or singular characters; simple relations, or dual characters; complex relations, or plural characters. Many lists of categories have been given not founded on formal logic.
2. n. A summum genus, or widest class.
3. n. Any very wide and distinctive class; any comprehensive division or class of persons or things.

Wiktionary

1. n. A group, often named or numbered, to which items are assigned based on similarity or defined criteria.
2. n. mathematics A collection of objects, together with a transitively closed collection of composable arrows between them, such that every object has an identity arrow, and such that arrow composition is associative.

GNU Webster's 1913

1. n. (Logic.) One of the highest classes to which the objects of knowledge or thought can be reduced, and by which they can be arranged in a system; an ultimate or undecomposable conception; a predicament.
2. n. Class; also, state, condition, or predicament.

WordNet 3.0

1. n. a general concept that marks divisions or coordinations in a conceptual scheme
2. n. a collection of things sharing a common attribute