Private Use TLD
A Private Use TLD is a DNS label that cannot correspond to any current or future delegation in the global DNS root. This reserved label would serve as a top-level domain (TLD) for a privately resolvable namespace with the goals of preventing collisions with globally delegated names, increasing predictability, and decreasing erroneous queries to root servers. The reason behind the recommendation for a private use TLD is that the ad hoc usage of TLDs for private purposes is currently uncoordinated and can harm Internet users. In SAC113, the SSAC recommended that the ICANN Board ensure a string reserved at the top level for private use and that it never be delegated. The SSAC proposed the following criteria for selecting the reserved string: It must be a valid DNS label, should not already be delegated in the root zone, should not be confusingly similar to existing TLDs, and should be relatively short, memorable, and meaningful.[1]