1. The process or technique of applying a secondary stain to a microscopic specimen after an initial stain, typically to highlight different cellular or bacterial structures.
Usage: technical; biology/microbiology

1. To apply a secondary stain to a microscopic specimen in order to differentiate structures or improve contrast.
Usage: technical; biology/microbiology

Examples

• Counterstaining with methylene blue helped reveal the bacterial nucleoid in the electron microscopy sample.
• The technician performed counterstaining after the initial Gram stain to enhance visibility of the cell walls.
• Counterstaining is essential in many histological procedures to distinguish between different tissue types.
• By counterstaining with safranin, the researchers could identify gram-negative bacteria more clearly.
• The lab protocol requires counterstaining all slides before microscopic examination.