- underworld - the criminal class
--1 is a kind of class, social class, socio-economic class
--1 has members: organized crime, gangland, gangdom; racketeer- Hel, Hell, Hades, infernal region, netherworld, Scheol, underworld - (religion) the world of the dead; "he didn't want to go to hell when he died"
--2 is a kind of imaginary place, mythical place
--2 has parts:Acheron, River Acheron; Cocytus, River Cocytus; Lethe, River Lethe; Styx, River Styx - Hel, Hell, Hades, infernal region, netherworld, Scheol, underworld - (religion) the world of the dead; "he didn't want to go to hell when he died"