In Jewish folklore, Lilith is said to have been Adam’s first wife. This story belongs to later folklore and mysticism, not to the Genesis account as it is usually read.
The best-known version appears in the medieval Alphabet of Ben Sira, generally dated to the eighth through tenth centuries. In that tale, Lilith was formed from the same earth as Adam, so she claimed equality with him. After refusing to submit, she left Eden, and Eve was later created as Adam’s companion.
The legend may have been encouraged by the two creation accounts in Genesis. Genesis 1 describes humanity as created male and female, while Genesis 2 gives a more detailed account of Eve being formed from Adam’s side. Later interpreters used this apparent difference to imagine an earlier woman.
Lilith has older and broader roots as a female night spirit or demon in Jewish and Near Eastern traditions. She is therefore not simply an alternative biblical name for Eve. Agrat and Naamah are other female figures in demonological folklore, while Lilith became the most famous supposed predecessor to Eve.