Congo red

noun

Con·​go red ˈkäŋ-(ˌ)gō- How to pronounce Congo red (audio)
: an azo dye C32H22N6Na2O6S2 that is red in alkaline and blue in acid solution and that is used especially as an indicator and as a biological stain

Word History

Etymology

Congo, territory in Africa

First Known Use

1885, in the meaning defined above

Time Traveler
The first known use of Congo red was in 1885

Dictionary Entries Near Congo red

Cite this Entry

“Congo red.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Congo%20red. Accessed 26 May. 2024.

Kids Definition

Congo red

noun
Con·​go red ˌkäŋ-ˌgō- How to pronounce Congo red (audio)
: a dye that is red in alkaline and blue in acid solution
Etymology

named for Congo, territory in Africa

Medical Definition

Congo red

noun
: an azo dye C32H22N6Na2O6S2 that is red in alkaline and blue in acid solution and that is used in a number of diagnostic tests and especially for the detection of amyloidosis since the injected dye tends to be retained by abnormal amyloid deposits

More from Merriam-Webster on Congo red

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!