Cerulean and Ultramarine

Cerulean adjective - Deep blue like the color of a clear October sky.

Ultramarine and cerulean are semantically related in sky topic. In some cases you can use "Ultramarine" instead an adjective "Cerulean".

Ultramarine adjective - Of a brilliant pure blue to purplish blue color.

Cerulean and ultramarine are semantically related in sky topic. You can use "Cerulean" instead an adjective "Ultramarine".