Click inside the address bar below to explore the different parts of a URL.
Your home has a unique address. Give anyone in the world your address and (given enough time and money) they could arrive on your doorstep.
Web pages need unique addresses too. These addresses allow you to find a particular page, as well as direct others to it. Giving each page a unique address is no easy task. The Internet is a network of networks, many of which are growing rapidly. In fact, new Web sites are added daily, each page in the site needing its own address. It's like having entire neighborhoods built in a day and each home needing an address immediately. That means a lot of naming and numbering, especially when you consider there are already billions of pages on the Internet that have already used up billions of names. Fortunately, there are enough parts to a Web address that it's fairly easy to create new ones.
The technical name for a Web address is URL, an acronym for uniform resource locator. Look at the top of your browser right now and you can see the URL for this page. It starts with http://. You've probably typed in a URL before to get to a particular Web page. Let's examine each part. We'll use for our example the URL for the Web site of the National Aeronautics and Space Administration—http://www.nasa.gov*.