Definition of orcein in English:


Pronunciation /ˈôrsēin/ /ˈɔrsiɪn/


  • A red dye obtained from orchil, used as a stain in microscopic study.

    ‘The chromosomes were stained with acetic orcein and visualized with a light microscope.’
    • ‘Chromosomes were counted in root tips stained with acetic orcein.’
    • ‘The slide was immersed in 1% orcein in 45% acetic acid for 15 min, washed in distilled water, air-dried and a coverslip was mounted in Histomount (National Diagnostics, Hull, UK).’
    • ‘After air drying, the cells were stained with 2% acetic orcein.’
    • ‘The anthers of each flower were squashed in a drop of 2% acetic orcein to intensify the staining of meiotic cells.’


Mid 19th century alteration of orcin, another name for orcinol.