1. existing, occurring, or done beneath the earth’s surface
2. secret or hidden from view
Usage: figurative

Examples

• The miners worked in subterranean tunnels deep below the city.
• Ancient subterranean caves were discovered during the excavation.
• The subway system creates a vast subterranean network beneath Manhattan.
• Subterranean water sources provide drinking water for many communities.
• The rebels operated through subterranean channels to avoid detection.
• Subterranean roots can extend far deeper than the visible plant above.