(1):
(n.) The blue vault above; the unclouded sky.
(2):
(n.) The clear blue color of the sky; also, a pigment or dye of this color.
(3):
(n.) The lapis lazuli.
(4):
(n.) A blue color, represented in engraving by horizontal parallel lines.
(5):
(v. t.) To color blue.
(6):
(a.) Sky-blue; resembling the clear blue color of the unclouded sky; cerulean; also, cloudless.