The local computer - your computer. It has IP address 127.0.0.1. Sometimes referred to as the 'loopback address'. Used when the computer need to "talk" to itself.

The loopback IP address for the local system; typically 127.0.0.1, but can be any address starting with 127.

refers to the local computer that a program is running on. For example, if you are running a Web browser on your computer, your computer is considered to be the "localhost." While this does not need to be specified when using a single computer, the localhost does need to be defined when running programs from multiple computers. For example, a network administrator might use his local machine to start a Web server on one system and use a remote access program on another. These programs would run from computers other than the localhost.

In computing the term localhost refers to the location of the currently used system. It is a loopback device which is assigned the IP address 127.0.0.1 in IPv4, or ::1 in IPv6, which can be used by TCP/IP applications to talk to themselves if this is needed.

Localhost is a software program that facilitates access to a peer-to-peer virtual file system via the Bit Torrent protocol. The program is a modification of Azureus version 2.3.0.4 and the two are backwards compatible.

This is usually (but not always) the name given to the host when the machine you are working on is the host.