Caching is when a version of a webpage is saved.
Caching is used in web development to make pages load faster. When a user visits a page, files are cached. Then, when the next person visits, the website can display the saved files which will load more quickly due to the cache.
Sometimes, a cached copy of a page is displayed by your browser. This explains why sometimes you might make a change to a webpage in your CMS, but your browser still shows you the old, cached version.
Google also has a cache of the last time it visited each page. You can see the cached version of a webpage by finding it in the search results and clicking on the little triangle and then clicking ‘Cached’.