θεῖον {θείων } [1 verse] (noun sg masc acc) "Brimstone" is theion, which in the form shown is either an adjective ( adj sg neut acc )  means "from or of the gods" or the adjective form ( part sg pres act neut acc ) of the verb that means to "shine" or "gleam", so "shining". However, it is more likely an alternative spelling  with a long "o" that is the verb that means "fumigate with brimstone" in the adjective form (part sg pres act neut acc) "gassing with sulfur". -- "Brimstone" is a Greek verb that the means to "fulminate with brimstone" in the form of an adjective so "gassing with sulfur" is the idea.  This word is in a form first seen in the Greek version of the Genesis describing the destruction of Sodom and Gomorrah.