Compounds in which the oxygen of an
aldehyde has been replaced by divalent sulfur,
RC(=S)H, e.g.
CH3CH2C(=S)H propanethial.
Source:
PAC, 1995, 67, 1307
(Glossary of class names of organic compounds and reactivity intermediates based on
structure (IUPAC Recommendations 1995))
on page 1372