v.tr. (-lying; past -lay; past part. -lain)
1. (also absol.) lie or be situated under (a stratum etc.).
2 (also absol.) (esp. as underlying adj.) (of a principle, reason, etc.) be the basis of (a doctrine, law, conduct, etc.).
3 exist beneath the superficial aspect of.
Etymology: OE underlicgan (as UNDER-, LIE(1))