noun
or thiocyanogen number
: a measure of unsaturation (as of an oil or fat) expressed usually as the number of grams or percentage of iodine equivalent to the thiocyanogen absorbed by 100 grams of the substance and serving as a supplement to the iodine number because thiocyanogen adds to double bonds to a different extent from the usual reagents for determining iodine number
the thiocyanogen value … is thus different from the ordinary value in that it differentiates between oleic, linoleic, and linolenic groups — T.P.Hilditch