From Paterva Wiki
The MX (mail exchange) records contains information about where mail should be sent for email addresses at the domain (for example mail for firstname.lastname@example.org should be sent to mx1.abc.com). You should understand the relationship between Domain, DNS Name and IP number as this system is one of the main building blocks of Internet.
Learn more about this entity
Domain name system on Wikipedia
See also (other entities)
Properties of this entity in Maltego
None - just the value.