Pronunciation: (un'dur-lī"ing), [key]
1. lying or situated beneath, as a substratum.
2. fundamental; basic: the underlying cause of their discontent.
3. implicit; discoverable only by close scrutiny or analysis: an underlying seriousness in his witticisms.
4. (of a claim, mortgage, etc.) taking precedence; anterior; prior.
5. Ling.belonging to an earlier stage in the transformational derivation of a sentence or other structure; belonging to the deep structure.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.