subsurface noun & adjective.
['sʌbsǝ:fɪs] L18.[from SUB- 1 + SURFACE noun.]A. noun. That which lies immediately below the surface;
spec. subsoil.
L18.b. adjective. Existing, lying, or operating under the surface of earth, water, etc.
L19. [TahlilGaran] English Dictionary ▲