1. existing, occurring, or operating beneath the surface of the earth or water

1. the area or region beneath the surface of the earth or water

Examples

• The subsurface layers of rock contain valuable minerals.
• Engineers studied the subsurface conditions before construction.
• Oil drilling requires knowledge of subsurface geology.
• The submarine explored the ocean’s subsurface.
• Scientists mapped the subsurface of the lake.
• Subsurface water flows through underground channels.
• The archaeologists discovered artifacts in the subsurface.