Synonyms and related words :
Caelus, air, azure, blue sky, caelum, canopy, canopy of heaven, cerulean, clear as glass, cope, empyrean, ether, firmament, glass, glasslike, glassy, heaven, heavens, hyalescent, lift, lifts, sky, starry heaven, the blue, the blue serene, vault, vault of heaven, vitreous, vitriform, welkin