Brimstone

originally denoted "fire from heaven." It is connected with sulphur. Places touched by lightning were called theia, and, as lightning leaves a sulphurous smell, and sulphur was used in pagan purifications, it received the name of theion, Luk 17:29, Rev 1:9-18, Rev 14:10, Rev 19:20, Rev 20:10, Rev 21:8.

akin to No. 1, signifies "brimstone-like, or consisting of brimstone," Rev 9:17.