KING’s POOL (בְּרֵכַ֖ת הַמֶּ֑לֶכְ). This is prob. identical with the Pool of Siloam (Neh 2:14), a reservoir of the king’s garden in Jerusalem.
International Standard Bible Encyclopedia (1915)
hamelekh): This is possibly the Pool of Siloam (Ne 2:14), and may have been so named as being near to the "king’s garden."