underlie

v. (-lying; past -lay; past part. -lain) 1 (also absol.) Lie under (a stratum etc.). 2 (also absol.) (esp. As underlying adj.) Be the basis of (a doctrine, conduct, etc.). 3 exist beneath the superficial aspect of.

v. t. To lie under; to rest beneath; to be situated under; as, a stratum of clay underlies the surface gravel.