Definition of counterstain in English:

counterstain

noun

Biology
  • An additional dye used in a microscopy specimen to produce a contrasting background or to make clearer the distinction between different kinds of tissue.

    • ‘Immunoreactivity was visualized using diaminobenzidine as the chromogen, with Harris modified hematoxylin as the counterstain.’
    • ‘Dapi was used as the chromosome counterstain for fluorescent specimens.’
    • ‘No counterstain was used on the sections, but routine coverslips were applied.’
    • ‘Harris hematoxylin was the counterstain for the remainder of the antibody reactions.’
    • ‘The shape of the nucleus was visualized using a DNA counterstain in all experiments.’

verb

[WITH OBJECT]Biology
  • Treat (a specimen) with a counterstain.

    • ‘After washing in tap water, specimens were briefly counterstained.’
    • ‘The chromosomes were counterstained with propidium iodide.’
    • ‘Slides were counterstained with hematoxylin, dehydrated, and mounted with glass coverslips.’
    • ‘The chromosomes are counterstained with DAPI (light blue).’
    • ‘Background material in the specimen was counterstained dull yellow to red.’

Pronunciation:

counterstain

/ˈkaʊntəˌsteɪn/