(business, US) A retailer that offers a wider selection of merchandise in a category than existing retailers, at lower prices, thereby gaining substantial share of the market and "killing" the existing retailers.

(linguistics) A linguistic category of words (or more precisely lexical items), generally defined by the syntactic or morphological behaviour of the lexical item in question, such as noun or verb.

A semantic or ontological error by which a property is ascribed to a thing that could not possibly have that property.

plural of lexical category

plural of category mistake

(category theory) A category whose objects are morphisms (of some given category) with a common codomain, and whose morphisms are commuting triangles where two morphisms of each of such triangles share the said common codomain.

(category theory) A category in which every bimorphism is an isomorphism.

(category theory) A category whose objects are functors (from some fixed given domain category to some fixed given codomain category) and whose morphisms are natural transformations.

(category theory) The category opposite to that of a slice category.

(category theory) A category built out of a pair of functors that have the same codomain.