There are two large groups or categories of domain names:
Generic domains or gTLDs are domain names which do not correspond to geographic criteria. They are managed by ICANN, the world authority in matters of domains, in conjunction with the bodies responsible for the maintenance of each type of domain (Verisign, PIR, Afilias, Neulevel, etc.). In recent years, hundreds of new types of extensions have been launched, with many types of categories ranging from geographic (.london, .paris), business (.company), or leisure (.dance), etc.
Territorial domains or ccTLDs are domains associated with a geographical location. Spain (.es) or France (.fr), for example. There are 252 territorial domains and they are formed of two letters which identify each country according to the ISP 3166 codes. They are managed by national bodies and in accordance with the registry regulations of each specific country.