a. - Pertaining to, or derived from, a sulphone; -- used
specifically to designate any one of a series of acids (regarded as
acid ethereal salts of sulphurous acid) obtained by the oxidation of
the mercaptans, or by treating sulphuric acid with certain aromatic
bases (as benzene); as, phenyl sulphonic acid, C6H5.SO2.OH, a stable
colorless crystalline substance.