Answer Description
A DMZ (Demilitarized Zone) is a part of a network that is somewhat protected, and allowed to be accessed externally and internally. However, it is also separated from the internal network, allowing a more secure environment internally.
Wikipedia
In computer security, a DMZ or demilitarized zone (sometimes referred to as a perimeter network or screened subnet) is a physical or logical subnetwork that contains and exposes an organization's external-facing services to an untrusted network, usually a larger network such as the Internet The purpose of a DMZ is to add an additional layer of security to an organization's local area network (LAN): an external network node can access only what is exposed in the DMZ, while the rest of the organization's network is firewalled The DMZ functions as a small, isolated network positioned between the Internet and the private network and, if its design is effective, allows the organization extra time to detect and address breaches before they would further penetrate into the internal networks
DMZ_(computing) - Wikipedia, the free encyclopedia