IP address
An IP address serves two principal functions. It identifies the host, or more specifically its network interface, and it provides the location of the host in the network, and thus the capability of establishing a path to that host. Its role has been characterized as follows: "A name indicates what we seek. An address indicates where it is. A route indicates how to get there."
The header of each IP packet contains the IP address of the sending host, and that of the destination host.
Host (network)
Computers participating in networks that use the Internet protocol suite may also be called "IP hosts". Specifically, computers participating in the Internet are called Internet hosts, sometimes "Internet nodes". Internet hosts and other IP hosts have one or more IP addresses assigned to their network interfaces. The addresses are configured either manually by an administrator, automatically at startup by means of the Dynamic Host Configuration Protocol (DHCP), or by stateless address autoconfiguration methods.