Ethionic :: Ethionic (a.) Pertaining to, derived from, or designating, an acid so called..
Isethionic :: Isethionic (a.) 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..
Methionic :: Methionic (a.) Of, pertaining to, or designating, a sulphonic (thionic) acid derivative of methane, obtained as a stable white crystalline substance, CH2.(SO3H)2, which forms well defined salts..