Definition

1. Noun:
   • A stain of a contrasting color used in microscopy or histology to make certain structures visible when the primary stain does not show them clearly. It provides a background or highlights different cellular components.

Usage

• Noun:
  • The biologist applied a counterstain to the tissue sample to differentiate the nucleus from the cytoplasm.
  • Safranin is commonly used as a counterstain in the Gram staining procedure to color Gram-negative bacteria pink.

Advanced Usage

• In a technical context: The term is primarily used in scientific disciplines like biology, histology, and pathology.
  • After the primary stain, a counterstain was applied to provide contrast and enhance the visualization of specific organelles.

Variants and Related Words

• Counterstaining (gerund/noun): The process or technique of applying a counterstain.
  • Counterstaining is a critical step in many histological protocols.
• Counterstained (adjective/verb, past participle): Describes a sample that has been treated with a counterstain.
  • The counterstained slide was ready for examination under the microscope.

Synonyms

• Secondary stain: A stain applied after the primary stain.
• Contrast stain: A stain used to provide a contrasting color.

Related Phrases/Idioms

(This term is highly technical and does not have common idiomatic or phrasal verb uses.)

Noun

1. a stain of contrasting color that is used when the principal stain does not show the structure clearly