ˈ ̷ ̷ ̷ ̷ˌ ̷ ̷ noun
Etymology: under (III) + world
1. archaic : the world lying below the heavens : earth
2. : the place of departed souls : hades
3.
a. : a region underground or in the ocean depths
b. : the side of the earth opposite to one
4.
a. : the world of activity among the lower forms of life
b. : a social sphere or level of society regarded as lying below the level of ordinary life and experience ; especially : the world of organized crime