An artificial red dye from which the Congo group received its name. It is also widely used either in aqueous solution or as test paper (Congo paper) for the detection of free acid, which turns it blue.
Webster's Revised Unabridged Dictionary
| APA | Webster's. (2011). congo red. Retrieved September 24, 2026, from http://smartdefine.org/congo_red/definitions/1990407 |
| Chicago | Webster's. 2011. "congo red" http://smartdefine.org/congo_red/definitions/1990407 (accessed September 24, 2026). |
| Harvard | Webster's 2011, congo red, Smart Define, viewed 24 September, 2026, <http://smartdefine.org/congo_red/definitions/1990407>. |
| MLA | Webster's. "congo red" 27 May 2011. Web. 24 September 2026. <http://smartdefine.org/congo_red/definitions/1990407> |