Homepage of a website
On the World Wide Web, a homepage is the starting point, or root of a website, a group of pages belonging to the same person, group, business or any other organization. The home page usually includes basic information on the theme of the whole website, and links to other related pages. It has the shortest URL: just the domain name.
Homepage of the browser
Most web browsers allow a particular URL to be designated as the homepage for the browser. This was in fact the original meaning of homepage: The first web page to be automatically connected to (sent an http request) upon launch of the browser.
Alternatively a local HTML-file can be specified, e.g. with links to frequently accessed websites, like bookmarks.
During the 1990s, many people considered homepage to refer to a person's containing information about themselves (such as a vanity site). This idea of a homepage is being superseded by the definition, above.