Longman Dictionary of Contemporary English
Wiktionary
n. 1 (context computing English) a unique, case-insensitive, name, consisting of a string made up of alphanumeric characters and dash separated by periods, that the Domain Name System map to IP numbers and other information. 2 an identifier of a computer or site on the Internet 3 a domain -- that part of a '''domain name''' which (nominally) identifies an organization; a '''domain name''' delegate 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 subdomain that are not delegated in turn.
WordNet
n. strings of letters used to name organizations and computers and addresses on the internet; "domain names are organized hierarchically with the more generic parts to the right"
Wikipedia
A domain name is an identification string that defines a realm of administrative autonomy, authority or control within the Internet. Domain names are formed by the rules and procedures of the Domain Name System (DNS). Any name registered in the DNS is a domain name. Domain names are used in various networking contexts and application-specific naming and addressing purposes. In general, a domain name represents an Internet Protocol (IP) resource, such as a personal computer used to access the Internet, a server computer hosting a web site, or the web site itself or any other service communicated via the Internet. In 2015, 294 million domain names had been registered.
Domain names are organized in subordinate levels (subdomains) of the DNS root domain, which is nameless. The first-level set of domain names are the top-level domains (TLDs), including the generic top-level domains (gTLDs), such as the prominent domains com, info, net, edu, and org, and the country code top-level domains (ccTLDs). Below these top-level domains in the DNS hierarchy are the second-level and third-level domain names that are typically open for reservation by end-users who wish to connect local area networks to the Internet, create other publicly accessible Internet resources or run web sites.
The registration of these domain names is usually administered by domain name registrars who sell their services to the public.
A fully qualified domain name (FQDN) is a domain name that is completely specified with all labels in the hierarchy of the DNS, having no parts omitted. Labels in the Domain Name System are case-insensitive, and may therefore be written in any desired capitalization method, but most commonly domain names are written in lowercase in technical contexts.
Usage examples of "domain name".
We're going to do some port surfing on this last AOL domain name server!
One of those had been a California state government computer in the western San Jose area - which he'd guessed was the CCU office, even though the domain name suggested it was a tourism organization.
He could always start deleting any e-mail that came without an @ sign and domain name.