- any general or comprehensive division; a class.
- a classificatory division in any field of knowledge, as a phylum or any of its subdivisions in biology.
- Metaphysics.
- (in Aristotelian philosophy) any of the fundamental modes of existence, such as substance, quality, and quantity, as determined by analysis of the different possible kinds of predication.
- (in Kantian philosophy) any of the fundamental principles of the understanding, as the principle of causation.
- any classification of terms that is ultimate and not susceptible to further analysis.
- a game in which a key word and a list of categories, as dogs, automobiles, or rivers, are selected, and in which each player writes down a word in each category that begins with each of the letters of the key word, the player writing down the most words within a time limit being declared the winner.
- a type of mathematical object, as a set, group, or metric space, together with a set of mappings from such an object to other objects of the same type.
- part of speech.
- a class or group of things, people, etc, possessing some quality or qualities in common; a division in a system of classification
- any one of the most basic classes into which objects and concepts can be analysed
- (in the philosophy of Aristotle) any one of ten most fundamental modes of being, such as quantity, quality, and substance
- (in the philosophy of Kant) one of twelve concepts required by human beings to interpret the empirical world
- any set of objects, concepts, or expressions distinguished from others within some logical or linguistic theory by the intelligibility of a specific set of statements concerning them
