category

Forms

1.A group, often named or numbered, to which items are assigned based on similarity or defined criteria.
- This steep and dangerous climb belongs to the most difficult category.
- I wouldn’t put this book in the same category as the author’s first novel.
2.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.
- One well-known category has sets as objects and functions as arrows.
- The use of the word ‘factor’ shows the explicit intention of categorists to work with functions in an algebraic manner: a category is an algebra of functions.

Common· #1609

Etymology tree

Proto-Indo-European *ḱe?

Proto-Indo-European *ḱóm

Proto-Indo-European *ḱm̥-th₂der.?

Proto-Hellenic *kətá

Ancient Greek κᾰτᾰ́ (kătắ)

Ancient Greek κᾰτᾰ- (kătă-)

Proto-Indo-European *h₂ger-

Proto-Indo-European *h₂goréh₂

Proto-Hellenic *agorā́

Ancient Greek ᾰ̓γορᾱ́ (ăgorā́)