IP address
An Internet Protocol address (IP address) is a numerical label assigned to each device connected to a computer network that uses the Internet Protocol for communication.
An IP address serves two principal functions: host or network interface identification and location addressing.
Provider-independent address space
A provider-independent address space (PI) is a block of IP addresses assigned by a regional Internet registry (RIR) directly to an end-user organization. The user must contract with an Internet service provider (or otherwise also known as a Local Internet Registry (LIR)) to obtain routing of the address block within the Internet.