1. Being or operating under the surface of the earth
   "subterranean passages"
   - subterraneous 
2. Lying beyond what is openly revealed or avowed (especially being kept in the background or deliberately concealed)
   "subterranean motives for murder"
   - subterraneous, ulterior

See also: covert, subsurface

Encyclopedia: Subterranean

• acousma
• acoustic
• acoustic aphasia
• acoustic buoy
• acoustic delay line
• acoustic device
• acoustic gramophone
• acoustic guitar
• acoustic impedance
• acoustic meatus
• acoustic modem
• acoustic nerve
• acoustic phenomenon
• acoustic power
• acoustic projection
• acoustic radiation pressure
• acoustic reactance
• acoustic resistance
• acoustic spectrum
• acoustic storage
• acoustic wave
• acoustical
• acoustically
• acoustician
• acousticophobia