An element of a Web page that establishes a context between the current page and another Web page or file on the World Wide Web. Also called a link, it can be used to immediately load the second Web page or file in a Web browser.

While nowadays mostly associated with Web pages the idea dates back a few years. The idea is to create links in a text document to other, related documents. If done right it enables the reader to find information more quickly and to go other ways than just the sequence of pages given by the author.