A cache is a stored, ready-made copy of your web pages that loads much faster than building each page from scratch every time. Caching is one of the biggest reasons a website feels fast - or doesn't.
Also known as: Page cache, caching plugin, browser cache
In plain English
Every time someone visits an uncached WordPress page, the server rebuilds it from scratch - database queries, plugin processing, theme rendering. A cache saves a finished copy of that page and hands it out instantly next time, skipping all the work.
Why it matters for your business
Caching is usually the single biggest speed win available on WordPress - often turning a 4-second load into under a second. Done wrong, though, it serves stale content: visitors see old prices, old pages, or changes that never appear.
When you'll run into it
On nearly every WordPress site. It's managed by a caching plugin or your host, and it needs clearing after updates or content changes.
Run into this on your site?
WordPress Care Plans