Every single registered domain name has no less than 2 Name Server records which show where it's hosted i.e. by using these records you direct your domain to the servers of a certain hosting provider. That way, you have got both your website and your emails handled by the very same company. On the lower level of the Domain Name System (DNS), nevertheless, there is a variety of other records, like A and MX. The first one reveals which server manages the website for a given domain and is always an IP address (123.123.123.123), while the second one indicates which server handles the e-mails and is always an alphanumeric string (mx1.domain.com). As an example, when you type a domain name in your Internet browser, your request is directed through the global DNS system to the provider whose NS records the domain name uses and from there you could be forwarded to the servers of a different company in case you have set an IP address of the latter as an A record for your domain address. Having different records for the site and the emails suggests that you can have your site and your emails with two different providers if you wish.