The Collaborative International Dictionary
Thiosulphuric
Thiosulphuric \Thi`o*sul*phur"ic\, a. [Thio- + sulphuric.] (Chem.) Of, pertaining to, or designating, an unstable acid, H2S2O3, analogous to sulphuric acid, and formerly called hyposulphurous acid.
Wiktionary
thiosulphuric
a. (context inorganic chemistry chiefly British English) (alternative spelling of thiosulfuric English)