Each domain name ends with a period and then two or three letters. These are called top level and each country has its own top level such as Norway: www.annec.no,
Sweden: www.annec.watching etc.
To be able to create a domain name in Norway (.no) one must have an organization number or be a Norwegian citizen. You can read more about the regulations surrounding .no domains at Norid.
There are also top-level domains that are not linked to a country but to a function and these are called generic top-level domains and have extensions such as www.annec.com, www.annec.Org etc.