Hypnos comes from the name of his Latin counterpart, Somnus. (in- "not" + somnus "sleep"), as well as a few less-common words such as "somnolent", meaning sleepy or tending to cause sleep and hypersomnia meaning excessive sleep, which can be caused by many conditions (known as secondary hypersomnia) or a rare sleep disorder causing excessive sleep with unknown cause, called Idiopathic Hypersomnia. 3D model of "Bronze head of Hypnos" via laser scan of a cast of British Museum's bronze. Hypnos In Greek mythology, Hypnos (; , "sleep") is the personification of sleep; the Roman equivalent is known as Somnus. In the
Pluto (mythology) Pluto (mythology) Pluto (Latin: "Plūtō"; , "") was the ruler of the underworld in classical mythology. The earlier name for the god was Hades, which became more common as the name of the underworld itself. In ancient Greek religion and mythology, Pluto represents a more positive concept of the god who presides over the afterlife. "Ploutōn" was frequently conflated with "Ploutos" (Πλοῦτος, Plutus), a god of wealth, because mineral wealth was found underground, and because as a chthonic god Pluto ruled the deep earth that contained the seeds necessary for a bountiful harvest. The name "Ploutōn" came into widespread usage