This definition is also listed under presence, site and Web site.
A Web site (we prefer the two words rather than Website) is a collection of Web files on a particular subject that includes a beginning file called a home page. For example, most companies, organizations, or individuals that have Web sites have a single address that they give you. This is their home page address. From the home page, you can get to all the other pages on their site. For example, the Web site for IBM has the home page address of http://www.ibm.com. (In this case, the actual file name of the home page file doesn't have to be included because IBM has named this file index.html and told the server that this address really means http://www.ibm.com/index.html.)
Since it sounds like geography is involved, a Web site can be confused with a Web server. A server in this context is a computer that holds the files for one or more sites. A very large Web site may reside on a number of servers located in many different geographic places. IBM is a good example; its Web site consists of thousands of files spread out over many servers in world-wide locations. But a more typical example is probably the site you are looking at, whatis.com. We reside on a commercial space provider's server with a number of other sites that have nothing to do with Internet glossaries.
A synonym and less frequently used term for Web site is "Web presence." That term seems to better express the idea that a site is not tied to specific geographic location, but is "somewhere in cyberspace." However, "Web site" seems to be used much more frequently.
You can have multiple Web sites that cross-link to files on each others' sites. This simply means that you've identified two starting places or home pages for all the files.
Some publications have begun using the term "Website." We prefer Web site.