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thymolphthalein

noun thy·mol·phtha·lein \ -ˈthal-ˌēn, -ˈthā-ˌlēn, -ˈthal-ē-ən \

medical Definition of thymolphthalein

: a crystalline compound C₂₈H₃₀O₄ analogous to phenolphthalein and likewise used as an acid-base indicator

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