RFC 822, P. Mockapetris, November 1983: This RFC introduces domain style names, their use for ARPA Internet mail and host address support, and the protocols and servers used to implement domain name facilities.
The purpose of this document is to explain the installation and upkeep of the BIND software package, and we begin by reviewing the fundamentals of the Domain Name System (DNS) as they relate to BIND. ... The Domain Name System (DNS) is the hierarchical, distributed database. It stores information for mapping Internet host names to IP addresses and vice versa, mail routing information, and other data used by Internet applications.