# adjoint

> English word · Adjective · IPA /ˈæd͡ʒ.ɔɪnt/ · frequency rank #65,669

## Definitions
1. Used in certain contexts, in each case involving a pair of transformations, one of which is, or is analogous to, conjugation (either inner automorphism or complex conjugation).
2. That is related to another functor by an adjunction.
3. Having a relationship of the nature of an adjoint (adjoint curve); sharing multiple points with.

## Etymology
From French adjoindre (“to join”), from late 19th C; see also adjoin. Doublet of adjunct.
In the case of category theory (which brings together concepts from numerous fields), the term is often confounded with adjunct and the relationship is called an adjunction. The origin of any particular usage may therefore be uncertain.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/adjoint