A blue colour on a coat of arms, represented in engraving by horizontal parallel lines.

The clear blue colour of the sky; also, a pigment or dye of this colour.

The unclouded sky; the blue vault above.

Any of various widely distributed lycaenid butterflies of the genus Celastrina.

Any of various Australasian lycaenid butterflies of the genus Ogyris.

Lapis lazuli.

To colour blue.