Apsu (Abzu)

In Mesopotamian cosmogony Apsu is the freshwater primordial ocean that, together with the saltwater Tiamat, gives rise to earlier generations of gods (for example Lahmu and Lahamu). Apsu exists from the beginning of the cosmos as the subterranean and surrounding freshwater principle; in Enūma Eliš the younger god Ea perceives the threat Apsu poses to the new generation, slays Apsu, takes Apsu's halo, and Apsu's domain becomes the dwelling of Ea and Damkina. Enūma Eliš further locates the birth of Marduk 'in the heart of Apsu,' where Ea and Damkina beget him.

Primary texts emphasize Apsu as the primordial freshwater abyss and a hypostatic divine presence rather than offering a consistent anthropomorphic iconography. Enūma Eliš and related summaries describe Apsu as the subterranean fresh-water ocean/abyss; later references note symbolic attributes (for example a 'halo' taken by Ea) but no stable corporeal depiction is preserved in the supplied material.

Apsu functions cosmologically as the source and regulator of fresh water: lakes, springs, rivers, fountains, rain and, in flood narratives such as Atrahasis, the Flood itself are said to originate from the Abzû/Apsu. Mythically Apsu is a progenitor in the divine genealogy and, in narrative sequences, an actor whose death by Ea results in transfer of his domain and the placement of later gods; his agency thus ranges from sustaining life through water to being a locus and participant in theogonies.