ὕαλος ὕᾰλος, or ὕελος, ὁ, ἡ, a clear, transparent stone, used by the Egyptians to enclose their mummies in, oriental alabaster, Hdt. a convex lens of crystal, used as a burning-glass, Ar. glass, Lat. vitrum, Plat.: glass itself existed in the time of Hdt., but was not called ὕαλος till Platoʼs time. The word is said to be Egyptian. Others refer it to ὕω, as if the orig. sense were raindrop.