A domain name is a human-readable label used to identify resources on the Internet. Instead of remembering numeric Internet Protocol (IP) addresses, people type names such as "example.com" into a browser or use them in email addresses. A domain name functions as both an address and an identifier and is resolved to an IP address by the Domain Name System (DNS), enabling routing of web, mail and other traffic.

Structure and components

Domain names are hierarchical and composed of parts separated by dots. Common components include:

  • Top-level domain (TLD): the rightmost label such as ".com", ".org" or country codes like ".uk".
  • Second-level domain (SLD): the name chosen by the registrant, located immediately left of the TLD, for example "example" in "example.com".
  • Subdomain: optional prefixes to the left that delegate or organize services, such as "www" or "mail".

How domain names work

When a user requests a domain, a DNS lookup translates the name into one or more IP addresses. Lookups may traverse recursive resolvers, root name servers, TLD name servers and authoritative name servers. DNS records (A, AAAA, MX, CNAME, TXT, SRV and others) indicate how different services are reached and which hosts handle mail or web traffic.

Registration, governance and types

Domain names are registered through accredited registrars under policies set by organizations such as ICANN for many global TLDs; individual country-code TLDs have their own rules. Types include generic TLDs (gTLDs), country-code TLDs (ccTLDs) and internationalized domain names (IDNs) that support non-Latin scripts. WHOIS services historically exposed registrant details, but privacy and data rules vary by jurisdiction.

Security, disputes and best practices

Security measures such as DNSSEC help verify that DNS responses are authentic; other technologies like DANE may tie certificates to DNS. Common problems include cybersquatting, typosquatting and phishing. Dispute resolution mechanisms such as the UDRP are used to resolve trademark conflicts. Best practices include choosing a memorable and appropriate name, keeping registration and DNS records current, enabling privacy protection where needed, and securing DNS and registrar accounts. For more technical background and operational guidance see DNS resources.