Phenol \Phe"nol\ (f[=e]"n[=o]l; 277), n. [Gr. fai`nein to show +
   -ol: cf. F. ph['e]nol.] (Chem.)
   1. A white or pinkish crystalline substance, C6H5OH,
      produced by the destructive distillation of many organic
      bodies, as wood, coal, etc., and obtained from the heavy
      oil from coal tar.
      [1913 Webster]

   Note: It has a peculiar odor, somewhat resembling creosote,
         which is a complex mixture of phenol derivatives. It is
         of the type of alcohols, and is called also phenyl
         alcohol, but has acid properties, and hence is
         popularly called carbolic acid, and was formerly
         called phenic acid. It is a powerful caustic poison,
         and in dilute solution has been used as an antiseptic.
         [1913 Webster]

   2. Any one of the series of hydroxyl derivatives of which
      phenol proper is the type.
      [1913 Webster]

   Glacial phenol (Chem.), pure crystallized phenol or
      carbolic acid.

   Phenol acid (Chem.), any one of a series of compounds which
      are at once a derivative of phenol and an organic acid;
      thus, salicylic acid is a phenol acid.

   Phenol alcohol (Chem.), any one of series of derivatives of
      phenol and carbinol which have the properties of both
      combined; thus, saligenin is a phenol alcohol.

   Phenol aldehyde (Chem.), any one of a series of compounds
      having both phenol and aldehyde properties.

   Phenol phthalein. See phenolphthalein.
      [1913 Webster]

Phenolphthalein \Phe`nol*phthal"e*in\, or Phenol phthalein
\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.
   [Webster 1913 Suppl. +PJC]

Phthalein \Phthal"e*in\, n. [See Phthalic.] (Chem.)
   One of a series of artificial organic dyes made as
   condensation products of the phenols with phthalic acid, and
   well represented by phenolphthalein. Their alkaline solutions
   are fluorescent.
   [1913 Webster]

   Phenol phthalein, a white or yellowish white crystalline
      substance made from phthalic acid and phenol. Same as
      phenolphthalein.
      [1913 Webster + PJC]