host(n) (1) A computer system that is accessed by a user working at a remote location. Typically, the term is used when there are two computer systems connected by modems and telephone lines. The system that contains the data is called the host, while the computer at which the user sits is called the remote terminal.
(3) To provide the infrastructure for a computer service. For example, there are many companies that host files, programs, applications or even a Web server for companies and individuals. In the case of a Web server, it means that they provide the hardware, software, and communications lines required by the server, but the content on the server may be controlled by someone else.