counterstain

verb

coun·​ter·​stain ˈkau̇n-tər-ˌstān 

counterstained; counterstaining; counterstains

transitive verb

: to stain (something, such as a microscopy specimen) so as to color parts (such as the cytoplasm of cells) not colored by another stain (such as a nuclear stain)

counterstain noun

Word History

First Known Use

1895, in the meaning defined above

Medical Definition

counterstain

1 of 2 noun

coun·​ter·​stain -ˌstān 

: a stain used to color parts of a microscopy specimen not affected by another stain

especially : a cytoplasmic stain used to contrast with or enhance a nuclear stain

counterstain

2 of 2 transitive verb

: to stain (a tissue or microscopy specimen) with an additional usually contrasting color