Thio vs thiono esters

[IngvarLa]

Opsin gives both ethyl thioacetate and ethyl thionoacetate as CC(=S)OCC, I thought the thioacetate should be CC(=O)SCC.

Wikipedia agrees with me:
https://en.wikipedia.org/wiki/Thioester
maybe not an authoritative source

[dan2097]

ethyl thionoacetate is unambiguous as thiono only refers to replacement of =O, but thio can refer to either -O- or =O. Strictly speaking ethyl thioacetate is ambiguous and IUPAC recommends O-ethyl thioacetate and S-ethyl thioacetate to disambiguate.

I do suspect you're right that far more often the thioester is intended when this is unspecified, but I'd like to do some empirical testing.