counterstain

Definitions

General Science

  • noun an additional stain applied to a specimen to be examined under a microscope, in order to bring out features not revealed by the primary stain
  • verb to use a counterstain on a microscope specimen

Medical

  • noun a stain used to identify tissue samples, e.g. red dye used to identify Gram-negative bacteria after having first stained them with violet dye
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