# thiosulfuric acid

> English word · Noun

## Definitions
1. An unstable acid, H₂S₂O₃, formally derived from sulfuric acid by the substitution of a sulfur atom in the place of an oxygen one; it is known only in solution or as its salts and esters, the thiosulfates.

## Etymology
From thio- + sulfuric acid.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/thiosulfuric-acid