1 definition by Meikyo

A prototype mobile suit.

NOTE: It is not an acronym, but in the newer series, Gundam SEED and Gundam SEED Destiny, it has been turned into an acronym quite definitions for the type(s) of Gundam O(perating)S(ystem)(s):

General
Unilateral
Neuro-Link
Dispersive
Autonomic
Manuver

Generation
Unrestricted
Network
Drive
Assault
Mode

Generation
Unsubdued
Nuclear
Drive
Assault
Module