noun
Etymology: so called from its use by Vandyke
1. usually capitalized V
a. : a deep-brown pigment of uncertain identity
b. : a natural brown-black pigment of poor light fastness obtained from bog earth or peat or lignite deposits, composed chiefly of organic matter with a small amount of ferric oxide, and used chiefly as an artist's color and stain — called also Cassel brown, Cologne brown
c. : any of various synthetic brown pigments (as a mixture of a carbon black with an iron-oxide red)
2. often capitalized V : a moderate brown that is redder, lighter, and slightly stronger than coffee, slightly redder, lighter, and stronger than chestnut brown, slightly yellower than auburn, and yellower and paler than bay — called also Cassel brown, Cologne brown, Cullen earth, Roman sepia, Verona brown