underlie

verb

1. (intransitive)To lie in a position directly beneath something.
2. (transitive)To lie under or beneath.

   “A stratum of clay underlies the surface gravel.”

3. (transitive)To serve as a basis of; form the foundation of.

   “a doctrine underlying a theory”

   “[…] she was carved into the bole of a red cedar tree. Sun and storm had bleached the wood, moss here and there softened the crudeness of the modelling; sincerity underlay every stroke.”

   “Some poems, echoing the purpose of early poetic treatises on scientific principles, attempt to elucidate the mathematical concepts that underlie prime numbers. Others play with primes’ cultural associations. Still others derive their structure from mathematical patterns involving primes.”

4. (transitive)To be subject to; be liable to answer, as a charge or challenge.

   “The knight of Ivanhoe […] underlies the challenge of Brian der Bois Guilbert.”

5. To underlay.