What is URL, or rather what is a URL?

What is URL?

A URL (Uniform Resource Locator, previously Universal Resource Locator) - usually pronounced 'Earl' or 'You Are El' - is the unique address for a file that is accessible on the Internet.
The URL consist of the name of the protocol (HTTP for webpages) PLUS a domain name that identifies a specific computer on the Internet PLUS a pathname (the location of a file on the server).
An example is http:// PLUS www.websites-biz-optimization.com PLUS /web-information.html which gives you http://www.website-biz- optimization.com/web-information.html