Domain Name System
The Domain Name System (DNS) is the hierarchical system whereby domain names are mapped to IP addresses on the Internet. It includes both the software services by which software can look up IP addresses as well as the commercial services through which individuals and organizations manage the registration and control of their domain names.
- domain name system (not capitalized) refers to any such system on any network
- domain name service refers to the software which provides domain-to-IP translation ability