Meaning

• 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

  "The boys in blue marched to the pipers."

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

• A member of law enforcement

• The sky, literally or figuratively.

  "His request for leave came out of the blue."

• 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.

Meaning

• 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.

Meaning

• Of the colour blue.

  "the deep blue sea"

• Depressed, melancholic, sad.

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

  "The candle burns blue."

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

• Of the higher-frequency region of the part of the electromagnetic spectrum which is relevant in the specific observation.

• (of steak) Extra rare; left very raw and cold.

• (of a dog or cat) Having a coat of fur of a slaty gray shade.

• Severe or overly strict in morals; gloomy.

  "blue and sour religionists;  blue laws"

• (of women) literary; bluestockinged.

• Having a color charge of blue.

• (entertainment) Risque or obscene

  "His material is too blue for prime-time"