Synonyms for Cerulean (same or very similar meaning)
WordNet sense 1 (a light shade of blue):
azure, sapphire, sky-blue, lazuline
WordNet sense 2 (of a deep somewhat purplish blue color similar to that of a clear October sky):
bright blue
WordNet sense 3 (being or having or characterized by hue):
chromatic
From the ODE community, based on WordNet
add/edit