\Un`der*lie"\, v. t. [AS. underlicgan. See {Under}, and
{Lie} to be prostrate.]
1. To lie under; to rest beneath; to be situated under; as, a
   stratum of clay underlies the surface gravel.
2. To be at the basis of; to form the foundation of; to
   support; as, a doctrine underlying a theory.
3. To be subject or amenable to. [R.]
         The knight of Ivanhoe . . . underlies the challenge
         of Brian der Bois Guilbert.           --Sir W.
                                               Scott.

\Un`der*lie"\, v. i.
To lie below or under.

\Un"der*lie`\, n.
See {Underlay}, n., 1.