Compounds having the structures RS2H, RS3H ... RSnH, in which Sn is a chain of sulfur atoms, and R is @H02891@. Some people exclude hydrodisulfides from the class hydropolysulfides.
Source: PAC, 1995, 67, 1307. (Glossary of class names of organic compounds and reactivity intermediates based on structure (IUPAC Recommendations 1995)) on page 1342 [Terms] [Paper]