from The American Heritage® Dictionary of the English Language, 4th Edition
- n. An unstable acid, H2S2O4, known only in aqueous solution and used as a bleaching and reducing agent. Also called hydrosulfurous acid.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. An unstable acid, H2SO4, only known in solution, used as a reducing agent; its salts are hydrosulfites (or hyposulfites).
Sorry, no etymologies found.