ˈjüˌglōn noun
( -s )
Etymology: International Scientific Vocabulary jugl- (from New Latin Juglans ) + -one; originally formed as German juglon
: a reddish yellow crystalline compound C 10 H 5 O 2 (OH) that is obtained especially from green shucks of walnuts and is the chief active principle of the brown hair dye from walnuts; 5-hydroxy-1, 4-naphthoquinone