The Webmaster's Lexicon: U

URL	Uniform Resource Locator. A specification of the location of a link. It specifies the protocol (http:// for a web page,) site name, path and file name to the resource. Think of it as a networked extension of the standard filename concept: not only can you point to a file in a directory, but that file and that directory can exist on any machine on the network, can be served via any of several different methods, and might not even be something as simple as a file: URLs can also point to queries, documents stored deep within databases, the results of a finger or archie command, or whatever.
Upload	The process of copying a file from your own computer to an online service, ftp site, website or remote computer.
Usability	Once a web visitor has reached your home page, can they use the rest of your site effectively? HTML and graphics are building blocks, but all too often the 'systems engineering' aspects of a web site are neglected. There are such issues as :- writing, aesthetics, style guides, accessibility, use of diagnostics tools, information architecture, etc. HTML standards and validation.