DNS

1) Domain Name System.  2) A service that stores, translates, and retrieves the numerical address equivalents of host names that a user accesses every day.  3) A tool created to help users to find their way around the Internet.

Source URL: 
http://www.google.com/url?q=http://en.wiktionary.org/wiki/DNS&sa=X&ei=3JIKTYjoB4O88gaB7tihAQ&ved=0CBoQpAMoAA&usg=AFQjCNEMJbN5z3_T78ThWnIZ5rg4boD6ig
http://www.google.com/url?q=http://4teachers.org/techalong/glossary/&sa=X&ei=3JIKTYjoB4O88gaB7tihAQ&ved=0CBwQpAMoAg&usg=AFQjCNHOkEXcGQJwwBPYSVl0bQkOiMj3Ng