Each registered domain name has no less than two Name Server records that show where it's hosted i.e. by using these records you direct your domain address to the servers of a certain website hosting company. In this way, you've got both your website and your emails managed by the exact same provider. On the lower level of the Domain Name System (DNS), nevertheless, there is a variety of other records, for example A and MX. The first one reveals which server handles the website for a given Internet domain and is always an IP address (188.8.131.52), while the latter reveals which server manages the e-mails and is always an alphanumeric string (mx1.domain.com). As an example, whenever you enter a domain name in your web browser, your request is sent through the global DNS system to the company whose NS records the domain uses and from there you will be forwarded to the servers of another company in case you have set an IP address of the latter as an A record for your domain name. Having different records for the site and the emails suggests that you could have your website and your emails with 2 different companies if you wish.