Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
An inflammable mineral substance found in quantities on the shores of the Dead Sea. The cities of the plain were destroyed by a rain of fire and brimstone (Gen. 19:24, 25). In Isa. 34:9 allusion is made to the destruction of these cities. This word figuratively denotes destruction or punishment (Job 18:15; Isa. 30:33, 34:9; Ps. 11:6; Ezek. 38:22). It is used to express the idea of excruciating torment in Rev. 14:10, 19:20, 20:10.