Synonyms and related words :
Caelus, aerosphere, air, atmosphere, azure, biosphere, blue sky, caelum, canopy, canopy of heaven, cerulean, cope, ecosphere, empyrean, ether, firmament, gaseous envelope, heaven, heavens, hyaline, lift, lifts, noosphere, sky, starry heaven, the blue, the blue serene, vault, vault of heaven