Morin

 A yellow crystalline substance (C15H10O7) of acid properties extracted from fustic (Chlorophora tinctoria syn. Maclura tinctoria, formerly called Morus tinctoria); -- called also moric acid and natural yellow 8. It is used as a dye for wool, giving a color from lemon yellow through olive to olive brown, depending on the metal with which it is mordanted.  [1913 Webster]