WordNet (r) 3.0 (2006):

Dead Sea
    n 1: a saltwater lake on the border between Israel and Jordan;
         its surface in 1292 feet below sea level

Easton's 1897 Bible Dictionary:

Dead Sea
   the name given by Greek writers of the second century to that
   inland sea called in Scripture the "salt sea" (Gen. 14:3; Num.
   34:12), the "sea of the plain" (Deut. 3:17), the "east sea"
   (Ezek. 47:18; Joel 2:20), and simply "the sea" (Ezek. 47:8). The
   Arabs call it Bahr Lut, i.e., the Sea of Lot. It lies about 16
   miles in a straight line to the east of Jerusalem. Its surface
   is 1,292 feet below the surface of the Mediterranean Sea. It
   covers an area of about 300 square miles. Its depth varies from
   1,310 to 11 feet. From various phenomena that have been
   observed, its bottom appears to be still subsiding. It is about
   53 miles long, and of an average breadth of 10 miles. It has no
   outlet, the great heat of that region causing such rapid
   evaporation that its average depth, notwithstanding the rivers
   that run into it (see JORDAN), is maintained with
   little variation. The Jordan alone discharges into it no less
   than six million tons of water every twenty-four hours.

     The waters of the Dead Sea contain 24.6 per cent. of mineral
   salts, about seven times as much as in ordinary sea-water; thus
   they are unusually buoyant. Chloride of magnesium is most
   abundant; next to that chloride of sodium (common salt). But
   terraces of alluvial deposits in the deep valley of the Jordan
   show that formerly one great lake extended from the Waters of
   Merom to the foot of the watershed in the Arabah. The waters
   were then about 1,400 feet above the present level of the Dead
   Sea, or slightly above that of the Mediterranean, and at that
   time were much less salt.

     Nothing living can exist in this sea. "The fish carried down
   by the Jordan at once die, nor can even mussels or corals live
   in it; but it is a fable that no bird can fly over it, or that
   there are no living creatures on its banks. Dr. Tristram found
   on the shores three kinds of kingfishers, gulls, ducks, and
   grebes, which he says live on the fish which enter the sea in
   shoals, and presently die. He collected one hundred and eighteen
   species of birds, some new to science, on the shores, or
   swimming or flying over the waters. The cane-brakes which fringe
   it at some parts are the homes of about forty species of
   mammalia, several of them animals unknown in England; and
   innumerable tropical or semi-tropical plants perfume the
   atmosphere wherever fresh water can reach. The climate is
   perfect and most delicious, and indeed there is perhaps no place
   in the world where a sanatorium could be established with so
   much prospect of benefit as at Ain Jidi (Engedi).", Geikie's
   Hours, etc.