Dictionary

The colour of the clear sky or the deep sea, between green and violet in the visible spectrum, and one of the primary additive colours for transmitted light; the colour obtained by subtracting red and green from white light using magenta and cyan filters; or any colour resembling this.

A blue dye or pigment.

Any of several processes to protect metal against rust.

Blue clothing

Example: The boys in blue marched to the pipers.

To make or become blue.

To treat the surface of steel so that it is passivated chemically and becomes more resistant to rust.

(laundry) To brighten by treating with blue (laundry aid)

To spend (money) extravagantly; to blow.

Of the colour blue.

Example: the deep blue sea

Depressed, melancholic, sad.

Pale, without redness or glare; said of a flame.

Example: The candle burns blue.

Supportive of, run by (a member of), pertaining to, or dominated by a political party represented by the colour blue.

(entertainment) Pornographic or profane.

Example: The air was blue with oaths.