---
tag: 0DKCECSYCF
kind: concept
name: Quadratic residue
msc: [11A15]
sources:
  - url: https://en.wikipedia.org/wiki/Quadratic_residue
    locator: lead section
same_as:
  wikidata: Q878259
  wikipedia: Quadratic residue
---

## Summary

A quadratic residue modulo $n$ is an integer that is congruent to a perfect square modulo $n$.
The [[definition of a quadratic residue|0SQDB87Z3T]] gives the precise form.