domain name

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A series of alphanumeric strings separated by periods, such as www.hmhbooks.com, that is an address of a computer network connection and that identifies the owner of the address.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun computing a unique, case-insensitive, name, consisting of a string made up of alphanumeric characters and dashes separated by periods, that the Domain Name System maps to IP numbers and other information.
• noun an identifier of a computer or site on the Internet
• noun a domain -- that part of a domain name which (nominally) identifies an organization; a domain name delegated to an independent administrative authority who is then responsible for the management of that portion of the Domain Name System's namespace that consist of the delegated domain and all subdomains that are not delegated in turn.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun strings of letters and numbers (separated by periods) that are used to name organizations and computers and addresses on the internet