Browser - A browser is a software application that is used to visit websites. Firefox, Internet Explorer, Safari, etc. If you think this is obvious, think again.

Server - When a webpage is visited, data is sent from some computer somewhere to your computer over the internet. That other computer is a server, essentially just like the one you are looking at, only specially configured to deliver information to other computers asking for it. Even though any computer could technically be a server, far more commonly people purchase server functionality from companies that specialize in it, like Media Temple. In addition to "server" being used to describe the physical machine, it also may be used to describe the software program used on that machine which handles serving up that data, like Apache.

URL - Uniform Resource Locator - is one of those things like this: http://css-tricks.com/video-screencasts/64-building-a-photo-gallery/ Some people also use URI - Uniform Resource Identifier - for the same purpose, although URL is far more common. I honestly read the entire Wikipedia article for both and I still don't really understand the difference. A domain name is the first part of the example above: css-tricks.com. Anybody can purchase a domain name, from companies like Go Daddy that specialize in it.