thioflavine

noun
thio·​fla·​vine | \ -ˈflā-ˌvēn How to pronounce thioflavine (audio) \
variants: also thioflavin \ -​ˈflā-​vən How to pronounce thioflavin (audio) \

Medical Definition of thioflavine

: either of two yellow thiazole dyes used as biological stains as well as in dyeing or making organic pigments