A Category

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

Synonyms

• (group to which items are assigned): class, family, genus, group, kingdom, order, phylum, race, tribe, type