'Thionic' definitions:

Definition of 'Thionic'

From: GCIDE

Thionic \Thi*on"ic\, a. [Gr. ? brimstone, sulphur.] (Chem.) Of or pertaining to sulphur; containing or resembling sulphur; specifically, designating certain of the thio compounds; as, the thionic acids. Cf. Dithionic, Trithionic, Tetrathionic, etc. [1913 Webster]