From The Art and Popular Culture Encyclopedia
In Classical Greek, Lethe literally means "forgetfulness" or "concealment". It is related to the Greek word for "truth": a-lethe-ia (αλήθεια), meaning "un-forgetfulness" or "un-concealment". In Greek mythology, Lethe is one of the several rivers of Hades: those who drank from it experienced complete forgetfulness. Lethe was also a naiad, although the naiad Lethe is probably a separate personification of forgetfulness rather than a reference to the river which bears her name. She was the daughter of Eris ('Strife' in Hesiod's Theogony), and sister to Algos, Limos, Horcus, and Ponos.