basement of a department store (where foodstuffs are usually sold)
 underground lake;  subterranean lake
 underground train;  subway
 underground space;  subterranean space;  subterranea
 underground shopping center;  underground shopping centre
 second basement level;  subbasement
 semibasement;  semi-basement
 underground organization;  underground organisation
 subway;  tube;  underground railroad;  underground railway
 member of a non-famous boy band or girl group; (lit.) underground idol
 basement floor;  underground floor
 underground activity;  underground activities;  underground movement
 underground shopping arcade connected to a station
 underground shopping arcade connected to a station
 underground shopping arcade connected to a station
 underground publication;  underground publishing;  samizdat
 burying;  underground installation (cables, etc.)
 clandestine bank;  underground bank
 underground economy;  black economy
 underground wire or cable
 underground train station
 underground activities;  secret maneuvering
 London Underground mosquito (Culex pipiens f. molestus)
 sunken hearth;  sunken fireplace