The Collaborative International Dictionary
fuming sulphuric acid
Disulphuric \Di`sul*phu"ric\, a. [Pref. di- + sulphuric.] (Chem.) Applied to an acid having in each molecule two atoms of sulphur in the higher state of oxidation.
Disulphuric acid, a thick oily liquid, H2S2O7, called also Nordhausen acid (from Nordhausen in the Harts, where it was originally manufactured), fuming sulphuric acid, and especially pyrosulphuric acid. See under Pyrosulphuric.
Wiktionary
fuming sulphuric acid
n. (context inorganic compound British English) (alternative spelling of fuming sulfuric acid English)