A unique string of numbers that identifies a computer on the Internet or other TCP/IP network.  The IP address is expressed in four groups of up to three numbers, separated by periods.  For example:  555.555.55.5.  An address may be "dynamic," meaning that it is assigned temporarily whenever a device logs on to a network or an Internet service provider and consequently may be different each time a device connects.  Alternatively, an address may be "static," meaning that it is assigned to a particular device and does not change, but remains assigned to one computer or device.