phenolphthalein

phe·nol·phtha·lein

noun
\ˌfēn-^əl-ˈthal-ē-ən, -ˈthal-ˌēn, -ˈthāl-\

Definition of PHENOLPHTHALEIN

: a white or yellowish white crystalline compound C₂₀H₁₄O₄ that is used in analysis as an indicator because its solution is brilliant red in alkalies and is decolorized by acids and that is used in medicine as a laxative