What is a domain?

If the Internet is a huge city, the domain names are the addresses of houses, shops and offices. There are billions, but each one has its own domain name - no two are alike. 

An address, in the language of the Net and computers, is only a sequence of numbers. Computers can store them without any problems - human beings, however, need to assign easy-to-remember addresses to words or phrases. The domain names are nothing more than sequences of letters and / or numbers, which users come up with themselves but such that they can be easily mremorized. They too, like the real addresses are unique and cannot be duplicated: a sequence of numbers will always correspond to just one domain name, and vice versa. Actually "translating" the names into numbers - the only language for machines - is up to other computers (Dns, Domain Name System ) in a completely invisible and transparent way.