WordNet (r) 3.0 (2006):

Gomorrah
    n 1: (Old Testament) an ancient city near the Dead Sea that
         (along with Sodom) was destroyed by God for the vice and
         depravity of its inhabitants [syn: Gomorrah, Gomorrha]

Easton's 1897 Bible Dictionary:

Gomorrah
   submersion, one of the five cities of the plain of Siddim (q.v.)
   which were destroyed by fire (Gen. 10:19; 13:10; 19:24, 28).
   These cities probably stood close together, and were near the
   northern extremity of what is now the Dead Sea. This city is
   always mentioned next after Sodom, both of which were types of
   impiety and wickedness (Gen. 18:20; Rom. 9:29). Their
   destruction is mentioned as an "ensample unto those that after
   should live ungodly" (2 Pet. 2:6; Jude 1:4-7). Their wickedness
   became proverbial (Deut. 32:32; Isa. 1:9, 10; Jer. 23:14). But
   that wickedness may be exceeded (Matt. 10:15; Mark 6:11). (See
   DEAD SEA).


Hitchcock's Bible Names Dictionary (late 1800's):

Gomorrah, rebellious people