noun
1.
a. : a strong blue that is greener and deeper than Sèvres and redder and darker than cerulean blue (sense 1b) — called also Leitch's blue
b. : a deep purplish blue that is less strong and very slightly redder than sapphire (sense 2a) and bluer and duller than hyacinth blue or Mazarine blue
2. also cyanine : a blue pigment consisting of a mixture of cobalt blue and Prussian blue — called also Leitch's blue
3. : cyanine 3