The Collaborative International Dictionary
Thienyl
Thienyl \Thi"["e]*nyl\, n. [Thiophene + -yl.] (Chem.) The hypothetical radical C4H3S., regarded as the essential residue of thiophene and certain of its derivatives.
Wiktionary
thienyl
n. (context organic chemistry especially in combination English) A univalent radical derived from thiophene