# cohomology

> English word · Noun · frequency rank #80,330

## Definitions
1. A method of contravariantly associating a family of invariant quotient groups to each algebraic or geometric object of a category, including categories of geometric and algebraic objects.
2. A system of quotient groups associated to a topological space.

## Etymology
From co- + homology.

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