The side or surface that is underneath; the bottom side. Also called undersurface.
The side that is less desirable, reputable, or noble than the obverse: "hunger, isolation, filth, the underside of [a] hellish regime” ( National Review).
American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.