---
tag: 0RZH6W98HK
kind: concept
name: Interior
aliases: [interior-of-a-set]
msc: [54A05]
sources:
  - url: https://en.wikipedia.org/wiki/Interior_(topology)
    locator: lead section
same_as:
  wikidata: Q862761
  wikipedia: Interior (topology)
---

## Summary

The interior of a subset of a topological space is the union of all open sets inside it.
It is the largest open set contained in the subset.