phenolphthalein

 
Pronunciation: /ˌfiːnɒlˈ(f)θaliːn, -ˈ(f)θeɪl-/

noun

[mass noun] Chemistry
  • a colourless crystalline solid (pink in alkaline solution) used as an acid-base indicator and medicinally as a laxative.
    • Chemical formula: C20H14O4

Origin:

late 19th century: from phenol + -phthal- (from naphthalene) + -in1