In computer networking, a network host, Internet host, host, or Internet node is a computer connected to the Internet - or more generically - to any type of data network. A network host can host information resources as well as application software for providing network services.
Every Internet host has one or more IP addresses uniquely assigned to the host. The addresses are assigned either manually by the computer administrator, or automatically at start-up by means of the Dynamic Host Configuration Protocol (DHCP).
Every host is a physical network node (i.e. a network device), but not every physical network node is a host. Network devices such as modems and network switches are usually not assigned host addresses, and are not considered hosts. Devices such as network printers and hardware routers are assigned IP addresses, but since they are not general-purpose computers, they are sometimes not considered as hosts.
Origin of the concept
The term terminal host denotes a multi-user computer or software providing services to computer terminals, or a computer that provides services to smaller or less capable devices. 
The term host is used in a number of RFCs that define the Internet and its predecessor ARPANET. The background is that while ARPANET was developed, computers connected to the network were typically main frame computer systems that could be accessed from terminals connected via serial ports. Since these dumb terminals did not contain software or perform computations themselves, they were not considered hosts. The terminals were not connected to the network, and were not assigned a IP address.
- End system
- Host model
- Internet hosting service