mythical river of Hades (whose water when drunk caused forgetfulness of the past), in Homer, a place of oblivion in the lower world; from Greek lēthē, literally "forgetfulness, oblivion," from PIE root *ladh- "be hidden" (see latent). Related to lēthargos "forgetful" and cognate with Latin latere "to be hidden." Also the name of a personification of oblivion, a daughter of Eris. Related: Lethean.
updated on January 12, 2019