Domain Name System is the system used on the Internet for mapping of names, such as www.google.com, to IP Addresses such as 216.239.51.99. In many ways you can compare it to a phonebook.

Domain name system (DNS) is the first thing you must use—whether or not you’re aware of that—before you can get “online.” ...

The primary name in a website address; for example, gmail.com, kmart.com and cnn.com. The domain names used for websites, email servers and all other facilities that transport data over the ...