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
Dragons in Greek mythology where it became the constellation Draco. Dragons in Greek mythology Dragons play a significant role in Greek mythology. The word dragon derives from the Greek δράκων (drakōn) and its Latin cognate draco. Ancient Greeks applied the term to large, constricting snakes. Daniel Ogden speaks of three ways to explain the origins of Greek dragon myths: as "vertical" evolution from (reconstructed) Proto-Indo-European mythology, as "horizontal" adaptation from Ancient Near Eastern mythology, or as sitting within "the cloud of international folktale". Regarding theories of vertical transmission, Ogden argues that they carry "an unspoken assumption that prior to such a transfer the Greeks'