1. The top-level entry point web page relating to an individual or institution, or possibly a subject area. This often has a url consisting of just a hostname, e.g. http://www.ncsa.uiuc.edu/. All other pages on a web site are usually accessible by following links from the home page.
2. The web page a user's web browser is configured to load each time it is started. This will typically default to the home page (sense 1) of the organisation that produced or distributed the browser.