from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Of, relating to, or situated in an area beneath a surface, especially the surface of the earth or of a body of water.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. Something that is below the layer that is on the surface.
- n. A surface which is a submanifold of another surface.
- adj. below the surface
from The Century Dictionary and Cyclopedia
- Being or occurring below the surface.
- n. A three-dimensional continuum in a space of five dimensions.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. beneath the surface
sub- + surface (Wiktionary)