1. a stain of contrasting color applied to a microscopic specimen to make certain structures more visible
Usage: scientific; microscopy

1. to apply a contrasting stain to a microscopic specimen
Usage: scientific; microscopy

Examples

• The lab technician applied a red counterstain to highlight the cell nuclei.
• Methylene blue serves as an effective counterstain in this procedure.
• After the primary stain, we counterstain the tissue sample with eosin.
• The counterstain made the bacteria clearly visible under the microscope.
• Students learned to counterstain their slides for better contrast.
• The pink counterstain revealed structures that were previously invisible.