Your domain name is essentially your signpost on the Internet. Every website you have ever visited uses a domain name in its address. People register domain names to stake a claim to a particular name — whether for business or personal reasons.
A domain name server provider is a company that sells domain name registrations to the public. Your domain provider is the last company you paid money to for your domain name registration. In all likelihood you paid money within the past year for your domain name renewal, transfer, or even its initial registration.