Webster’s Revised Unabridged Dictionary · 1913
Isethionic
I·seth′i·on′ic (ī·sĕth′ī·ŏn′ĭk), a. [Is- + ethionic.] (Chem.) Pertaining to, derived from, or designating, an acid, HO.C2H4.SO3H, obtained as an oily or crystalline substance, by the action of sulphur trioxide on alcohol or ether. It is derivative of sulphuric acid.