What is a domain name ?
This is an Internet address, consisting of a name that you choose and an extension (tld). It is most often used for naming a website (eg www.francedns.com) or email address (firstname.lastname@example.org).
The domain is associated with an IP address that identifies a computer or server on which the services will be available (website, mail boxes, etc.) .. The domain name is awarded for one year minimum renewable and associated IP address by DNS.
In terms of syntax, the name consists of a word or sequence of numbers or a combination thereof, and an extension separated by a point. You can still add names to a subdomain, which is generally a sub-directory in the address field. The maximum size of name is 63 characters (excluding extension or subdomain).
The system rules are defined by naming the supervisory authorities (eg ICANN), the databases are centralized in registries (such as Verisign for .com, AFNIC for .fr), and marketing and ongoing management is provided by registrars such as FranceDNS.