Domain Name System (DNS) – a hierarchical distributed network name system that responds to queries for domain names. So much for the encyclopedia.
And what is it in practice?
DNS acts like a dictionary that translates text addresses (e.g. https://bezpiecznyblog.pl) into IP addresses (e.g. 172.178.0.1) so that we don’t have to memorize strings of a few or a dozen digits to get to the site we’re interested in.
It is also a complicated legal system that ensures that domains can be registered and linked to IP addresses around the world.