Find the word definition

The Collaborative International Dictionary
Isethionic

Isethionic \I*seth`i*on"ic\, 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.

Wiktionary
Wikipedia