cerulean vs sky-blue

cerulean and sky-blue both are nouns.

Word	Noun	Adjective	Verb	Adverb
cerulean	Yes	Yes	No	No
sky-blue	Yes	Yes	No	No

As adjectives, cerulean and sky-blue are synonyms defined as:

cerulean and sky-blue: of a deep somewhat purplish blue color similar to that of a clear October sky

Other synonyms of cerulean include azure, bright blue.

As nouns, cerulean and sky-blue are synonyms defined as:

Other synonyms of cerulean include azure, lazuline, sapphire.

cerulean (noun)	sky-blue (noun)
a light shade of blue	a light shade of blue

cerulean (adjective)	sky-blue (adjective)
of a deep somewhat purplish blue color similar to that of a clear October sky	of a deep somewhat purplish blue color similar to that of a clear October sky