blue

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

(in the plural) A blue uniform. See blues.

A member of law enforcement

The sky, literally or figuratively.

The ocean; deep waters.

The far distance; a remote or distant place.

Anything blue, especially to distinguish it from similar objects differing only in color.

A dog or cat with a slaty gray coat.

One of the colour balls used in snooker, with a value of five points.

Any of the butterflies of the subfamily Polyommatinae in the family Lycaenidae, most of which have blue on their wings.

A bluefish.

An argument.

A liquid with an intense blue colour, added to a laundry wash to prevent yellowing of white clothes.

A type of firecracker.

A bluestocking.

One of the three color charges for quarks.