Learn in the textbookDomain Names, DNS, and How the Web Works
DefinitionDNS is a system that keeps track of which domain names go with which IP addresses and, when asked, uses one to look up the other.
ExplanationConverting between names and IP addresses is called name resolution (名前解決). When you enter a name in a browser, the PC first queries a DNS server (DNS サーバ), then connects using the IP address it gets back. The lookup also works the other way, from an IP address to a name.
AnalogyThink of a directory-assistance desk: give the person's name and it tells you their phone number.
Memory hookThe full name is Domain Name System; let the Name in the middle remind you of the clerk who looks up names.