the DNS which stands for "Domain Names System", others might say it stands for "Domain Names Service" both are OK.

DNS is a distributed database of computers that convert between IP address and hostnames.

for example, you are visiting this page through the DNS name of Webune.com - your computer doesn't use DNS, it uses IP address to reach this website, so to interact between you and the computer you have DNS.

if there was no DNS, then you would have to remember the IP address for this website, instead of Webune.com -

Webune.com is just more easy to remember. thats why there DNS, so you can remember more easy