Available Definitions:
1) v. t. - To lie under; to rest beneath; to be situated under; as, a stratum of clay underlies the surface gravel.
2) v. t. - To be at the basis of; to form the foundation of; to support; as, a doctrine underlying a theory.
3) v. t. - To be subject or amenable to.
4) v. i. - To lie below or under.
5) n. - See Underlay , n., 1.