1. the world of the dead; the underworld in mythology and religion
Usage: mythology; religion
2. a hidden or secret world, especially one involving criminal activity

Examples

• In Greek mythology, Hades ruled over the netherworld.
• The detective investigated the city’s criminal netherworld.
• Ancient cultures had various beliefs about the netherworld.
• She wrote a novel about a hero’s journey through the netherworld.
• The journalist exposed the netherworld of illegal gambling.
• Many religions describe a netherworld where souls go after death.