orcein (AWR-see-in) - n., a purplish-red dye, related to litmus, extracted from Rocella tinctoria and related lichens.
Used as a dye in histology and formerly used as a food coloring. It's a slightly later alteration of cudbear, the first dye invented in modern times in the 1770s. The name was altered from orcin or orcinol, an intermediate compound in the processing, which in turn is from orchil or archil or orchella, names for the lichens, from Italian orcello, from Old French orcheil, of uncertain origin.
---L.
Used as a dye in histology and formerly used as a food coloring. It's a slightly later alteration of cudbear, the first dye invented in modern times in the 1770s. The name was altered from orcin or orcinol, an intermediate compound in the processing, which in turn is from orchil or archil or orchella, names for the lichens, from Italian orcello, from Old French orcheil, of uncertain origin.
---L.