The Okinawa word Gusuku is written with the Chinese character for castle and generally refers to a castle or fortification. However, due to the diversity of the form and function in the areas that use this designation, the genuine etymology of this word is still controversial.
So far the historical references have frequently referred to a Gusuku as the place where an Aji chieftain lived. There are, however, theories that state that the essence of the word indicates a stone enclosed sacred precinct and another which theorizes that it refers to an enclosure built for protection by the early villagers. Whether it is simply a stone enclosure or an accented way of saying Ushuku, or place to stay, there are diverse theories as the origin of the word.
As it is yet to be fully elucidated and yet occupies a substantial place within the history of the Ryukyus, new research is eagerly awaited which will solve the mystery of these ancient ruins.