Dictionary.net

• A peculiar colouring matter obtained from a species of lichen.

1874 - Etymological and pronouncing dictionary of the English language
By Stormonth, James, Phelp, P. H.

• or'sin, n. a colouring matter obtained from orchella-weed and other lichens.

1908 - Chambers's Twentieth Century Dictionary of the English Language
By Thomas Davidson