cerulean blue

1a :  a variable color averaging a strong greenish blue that is bluer and duller than grotto or cobalt blue and bluer and lighter than indigo carmine b :  a strong blue that is greener and stronger than Sèvres and greener, lighter, and stronger than Victoria blue —called also coelin

2 :  a stable light greenish blue pigment consisting essentially of oxides of cobalt and tin and used as an artist's color