An IP Address is a numeric address such as 209.153.19.153 that indenties a host or device on a TCP/IP network. Each IP Address exposed to the public Internet is unique. The current standard is IPv4 which due to the remarkable growth of the Internet is slowly being replaced by the next generation IPv6. With IPv4 each IP Address is made up of four octets.
See also:
Octet
Subnet
A Record