An acconym used by Discowrld fans to commemorate people who have passed on. The origin is the novel Going Postal by Sir
Terry Pratchett, in which semaphore operators send the names of their
fallen comrades back and forth along the semaphore system, known as the
clacks, with this code attached.
The code translates as follows:
G: General broadcast, send in all directions
N: Do not log the mmessage
U: Sent the message back when it reaches the end of the line
By sending the code and the name the operators are asking to keep the persons name cycling the system for ever. Similar to the notion that a person is never gone while others still speak their name.