There are some opinions where the name is derived from, including from the fact that the pond water depends on the Yoshiki-gawa River, or the pond is shaped like the Chinese character 'Water' in the Sosho-tai (cursive style writing), or it was taken from a phrase 'Meien ha Ryokusui ni Yori' (The beautiful garden to go is spread along the green water) of a poem written by Toho (a Chinese poet), however, none of them is not certain.
池が吉城川の水に依っているためという説や、然庭園内の池が草書体の水の形をしていることに由来するという説、杜甫の「名園緑碌水」の句に由来するなどの説があるが、はっきりしたことは分かっていない。