Internet Protocol Address

An IP Address or "Internet Protocol Address" is the address of a device that is connected to a network.  The connected device is normally a personal computer (i.e. client) or a server computer.

An IP Address can either be static or dynamic. Server computers and network device that need to be accessed by multiple clients normally use static addresses.

Personal computer connected to the Internet could either have a static or dynamic IP address.

World Wide Web - Conceptual Overview

For example, each time a mobile device connects to the Internet, a different IP address is normally assigned.  Hard-wired computer connections, however, often have static connections.

Registries such as ARIN (the American Registry for Internet Numbers) are responsible for assigning blocks of IP addresses to organizations that are then free to allocate the addresses as they like.