---
tag: 049PXYHW1T
kind: concept
name: Open cover
msc: [54D30]
sources:
  - url: https://en.wikipedia.org/wiki/Cover_(topology)
    locator: Definition
---

## Summary

An open cover of a subset of a topological space is a family of open sets whose union contains the subset.
Open covers are used to define compactness.