Brimstone \Brim"stone\, n. [OE. brimston, bremston, bernston, brenston; cf. Icel. brennistein. See Burn, v. t., and Stone.] Sulphur; See Sulphur.
Source: Webster's Revised Unabridged Dictionary (1913)
Brimstone \Brim"stone\, a. Made of, or pertaining to, brimstone; as, brimstone matches.
From his brimstone bed at break of day A-walking the devil has gone. --Coleridge.