The Collaborative International Dictionary of English v.0.48:

Nitroglycerin \Ni`tro*glyc"er*in\, Nitroglycerine
\Ni`tro*glyc"er*ine\(n[imac]`tr[-o]*gl[i^]s"[~e]r*[i^]n), n.
   [Nitro- + glycerin.] (Chem.)
   A liquid appearing like a heavy oil, colorless or yellowish,
   and consisting of a mixture of several glycerin salts of
   nitric acid, and hence more properly called glycerin
   nitrate; also called trinitroglycerin and glyceryl
   trinitrate. It is made by the action of nitric acid on
   glycerin in the presence of sulphuric acid. It is extremely
   unstable and terribly explosive. A very dilute solution is
   used in medicine as a neurotic under the name of glonion.
   [Written also nitroglycerine.]
   [1913 Webster]

   Note: A great number of explosive compounds have been
         produced by mixing nitroglycerin with different
         substances; as, dynamite, or giant powder,
         nitroglycerin mixed with siliceous earth;
         lithofracteur, nitroglycerin with gunpowder, or with
         sawdust and nitrate of sodium or barium; Colonia
         powder, gunpowder with nitroglycerin; dualin,
         nitroglycerin with sawdust, or with sawdust and nitrate
         of potassium and some other substances; lignose, wood
         fiber and nitroglycerin.
         [1913 Webster]

WordNet (r) 3.0 (2006):

trinitroglycerin
    n 1: a heavy yellow poisonous oily explosive liquid obtained by
         nitrating glycerol; used in making explosives and medically
         as a vasodilator (trade names Nitrospan and Nitrostat)
         [syn: nitroglycerin, nitroglycerine,
         trinitroglycerin, glyceryl trinitrate, Nitrospan,
         Nitrostat]