APSU. - It is a Semitized Sumerian word, which in Sumerian was written ZU-AB and read abzu, with the meaning “house of wisdom” (?). This etymology (ab “house,” zu “wisdom”?) is necessarily correlated with the fact that a. is the dwelling-place of Ea, god of wisdom. The a., the dwelling-place of the wise god, is the mass of water upon which the earth rests and which surrounds II. The a. is above as well as beneath the earth; from the a. above, from heaven, come the rains; from the a. below, the waters of rivers and streams that give fertility to the earth. An analogous cosmogonic conception is found in Genesis. Some suppose that the Greek abyssa and the derivatives in the Indo-European languages also go back to this Sumerian word.
A. is also a male divinity, “the ocean of fresh water,” whose mother is the goddess Tiamat, “the ocean of salt water.” The god A. is subsequently slain by the god Ea. It is perhaps from this legend that a. becomes the dwelling-place of the god Ea.