What is a webpage?

A webpage is simply a file which lives on a web server. It can contain a varety of elements, such as images, text hyperlinks (or just 'links') and many others.

What is a website?

All that makes up a website is a collection of webpages, which are hosted on a web server.

What is a web server?

A web server is pretty much a computer which holds webpages and other files which is connected to the internet 24 hours a day, 365 days a year. In theory your home computer can act as a web server, although this wouldn't always be a good idea!