1.nounThe compound glyceryl-tri-nitrate or 1,2,3 tri-nitrooxy propane; the ester of glycerol with nitric acid; prepared by the careful addition of a mixture of nitric and sulphuric acids to glycerol with constant stirring and cooling; it is a thick, pale yellow liquid, that is highly explosive on concussion or on exposure to sudden heat; it is used in medicine as a vasodilator, and as an explosive in the form of dynamite which is safe to handle.