Ki was the earth goddess in Sumerian mythology, chief consort of the sky god An. In some legends Ki and An were brother and sister, being the offspring of Anshar ("Sky Pivot") and Kishar ("Earth Pivot"), earlier personifications of heaven and earth.
By her consort Anu, Ki gave birth to the Anunnaki, the most prominent of these deities being Enlil, god of the air. According to legends, heaven and earth were once inseparable until Enlil was born; Enlil cleaved heaven and earth in two. An carried away heaven. Ki, in company with Enlil, took the earth.
Some authorities question whether Ki was regarded as a deity since there is no evidence of a cult and the name appears only in a limited number of Sumerian creation texts. Samuel Noah Kramer identifies Ki with the Sumerian mother goddess Ninhursag and claims that they were originally the same figure.
She later developed into the Babylonian and Akkadian goddess Antu, consort of the god Anu (from Sumerian An).
Cuneiform KI (Borger 2003 nr. 737; U+121A0 𒆠) is the sign for "earth". It is also read as GI5, GUNNI (=KI.NE) "hearth", KARAŠ (=KI.KAL.BAD) "encampment, army", KISLAḪ (=KI.UD) "threshing floor", and SUR7 (=KI.GAG).
In Akkadian orthography, it functions as a determiner for toponyms and has the syllabic values gi, ge, qi, and qe.