Web, domains and email
MX
Abbreviation for Mail Exchange
In short and in plain language
An MX record is an entry in the domain name system.
It says which server takes in email for a domain.
Without a fitting record, mail to your own address does not arrive.
An empty record can show that a domain does not receive email.
Definition
An MX record is an entry in the Domain Name System that states which server accepts email for a domain. Without a suitable record, mail sent to your own address does not arrive. A null record can signal that a domain does not receive email.