phe·nol·phtha·lein /ˌfinḷˈθæliən, ˈθæˌlin, ˈθe-/
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 phe·nol·phtha·lein /ˌfɪnḷˈθælɪən, ˈθælˌɪn, ˈθel-/ 名詞
 Phe·nol·phthal·e·in or Phenol phthalein., n. Chem. A white or yellowish white crystalline substance, C20H14O4, formed by condensation of the anhydride of phthalic acid and phenol. Its solution in alkalies is brilliant red, but is decolorized by acids.  This reaction, being very delicate, is used as a pH indicator.  It is sometimes used as a laxative in veterinary medicine.
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 phenolphthalein
      n : a laxative used in many preparations under various trade
          names; also used as an acid-base indicator in titrations
          involving weak acids and strong bases because it is
          brilliant red at high alkalinity and colorless below pH 8