thiochrome

noun
thio·​chrome | \ ˈthī-ə-ˌkrōm How to pronounce thiochrome (audio) \

Medical Definition of thiochrome

: a yellow crystalline tricyclic alcohol C12H14N4OS found in yeast, formed by oxidation of thiamine, and giving a blue fluorescence under ultraviolet light that serves as the basis of a method of determining thiamine