Zip file
A zip file is one folder squeezed into a single file, so many files travel together.
In a simple example
You download one zip of your website, open it on your computer, and all the pages and pictures are inside.
Why it matters to you
It is how a finished website reaches you: one download that holds everything.
Do not confuse with
A zip is a package, not a website. You open it first, then put its files online.