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  • blue
    blue
    noun
    the pure color of a clear sky; the primary color between green and violet in the visible spectrum, an effect of light with a wavelength between 450 and 500 nanometers.
  • Blue
    Blue
    noun
    a nickname for a person with red hair
Synonyms

blue

American  
[bloo] / blu /

noun

  • blues
    plural
  1. the pure color of a clear sky; the primary color between green and violet in the visible spectrum, an effect of light with a wavelength between 450 and 500 nanometers.

    Synonyms:
    sapphire, cerulean, azure
  2. bluing.

  3. something having a blue color.

    Place the blue next to the red.

  4. a person who wears blue or is a member of a group characterized by some blue symbol.

    Tomorrow the blues will play the browns.

  5. (often initial capital letter) a member of the Union army in the American Civil War or the army itself.

  6. bluestocking.

  7. blue ribbon.

  8. any of several blue-winged butterflies of the family Lycaenidae.

  9. Printing. blueline.

  10. the blue,

    1. the sky.

    2. the sea.

    3. the remote distance.

      They've vanished into the blue somewhere.


adjective

bluer, bluest
  1. of the color of blue.

    a blue tie.

  2. (initial capital letter) of or relating to the Union army in the American Civil War.

  3. (of the skin) discolored by cold, contusion, fear, or vascular collapse.

  4. depressed in spirits; dejected; melancholy.

    She felt blue about not being chosen for the team.

    Synonyms:
    downcast, glum, sad, dispirited, doleful, morose, unhappy, despondent
    Antonyms:
    happy
  5. holding or offering little hope; dismal; bleak.

    a blue outlook.

    Synonyms:
    gloomy
  6. characterized by or stemming from rigid morals or religion.

    statutes that were blue and unrealistic.

    Synonyms:
    strait-laced, puritanical, righteous
  7. marked by blasphemy.

    The air was blue with oaths.

  8. (of an animal's pelage) grayish-blue.

  9. indecent; somewhat obscene; risqué.

    a blue joke or film.

  10. Politics.

    1. relating to, supporting, or belonging to the Democratic Party in the United States; Democratic.

      The county effectively turned blue, with all 38 district judges elected being Democrats.

    2. British. politically conservative.

verb (used with object)

  • blues,
    present (3rd person singular)
  • blued,
    past participle,  past
  • bluing,
    present participle
  • blueing
    present participle
  1. to make blue; dye a blue color.

  2. to tinge with bluing.

    Don't blue your clothes till the second rinse.

verb (used without object)

  • blues,
    present (3rd person singular)
  • blued,
    past participle,  past
  • bluing,
    present participle
  • blueing
    present participle
  1. to become or turn blue.

idioms

  1. out of the blue, suddenly and unexpectedly.

    The inheritance came out of the blue as a stroke of good fortune.

  2. blue in the face, exhausted and speechless, as from excessive anger, physical strain, etc..

    I reminded him about it till I was blue in the face.

blue 1 British  
/ bluː /

noun

  1. any of a group of colours, such as that of a clear unclouded sky, that have wavelengths in the range 490–445 nanometres. Blue is the complementary colour of yellow and with red and green forms a set of primary colours

  2. a dye or pigment of any of these colours

  3. blue cloth or clothing

    dressed in blue

    1. a sportsperson who represents or has represented Oxford or Cambridge University and has the right to wear the university colour (dark blue for Oxford, light blue for Cambridge)

      an Oxford blue

    2. the honour of so representing one's university

  4. an informal name for Tory

  5. any of numerous small blue-winged butterflies of the genera Lampides, Polyommatus , etc: family Lycaenidae

  6. archaic short for bluestocking

  7. slang a policeman

  8. archery a blue ring on a target, between the red and the black, scoring five points

  9. a blue ball in snooker, etc

  10. another name for blueing

  11. slang an argument or fight

    he had a blue with a taxi driver

  12. Also: blueyslang a court summons, esp for a traffic offence

  13. informal a mistake; error

  14. apparently from nowhere; unexpectedly

    the opportunity came out of the blue

  15. into the unknown or the far distance

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

adjective

  1. of the colour blue

  2. (of the flesh) having a purple tinge, as from cold or contusion

  3. depressed, moody, or unhappy

  4. dismal or depressing

    a blue day

  5. indecent, titillating, or pornographic

    blue films

  6. bluish in colour or having parts or marks that are bluish

    a blue fox

    a blue whale

  7. rare aristocratic; noble; patrician See blue blood

    a blue family

  8. relating to, supporting, or representing the Democratic Party Compare red 1

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. to make, dye, or become blue

  2. (tr) to treat (laundry) with blueing

  3. slang (tr) to spend extravagantly or wastefully; squander

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Blue 2 British  
/ bluː /

noun

  1. informal a nickname for a person with red hair

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

blue More Idioms  

    More idioms and phrases containing blue


Other Word Forms

Derived Forms

Inflected Forms

Nouns

Participles

Conjugated Forms

Present

Past

Future

Etymology

Origin of blue

First recorded in 1250–1300; Middle English blewe, from Anglo-French blew, bl(i)u, bl(i)ef “blue, livid, discolored,” Old French blo, blau ( French bleu ), from unattested Germanic blǣwaz; compare Old English blǣwen, contraction of blǣhǣwen “deep blue, perse,” Old Frisian blāw, Middle Dutch blā(u), Old High German blāo ( German blau ), Old Norse blār

Explanation

Among other things, blue is a color and a dreary mood. If the blue sky and ocean have turned gray and stormy, you might be blue because your day at the beach is ruined. Whether it's a primary color or a saddened mood, blue is used often as an adjective for people and things. Blue is a mix of green and purple shades, and it's the favorite color of many. The color blue might bring thoughts of first-place blue ribbons or police officers in blue uniforms, and it colors many flags of the world. Blue is everywhere, but there isn't a lot of blue food unless it's colored with dye. Even blueberries are mostly purple.

Keep Reading on Vocabulary.com

Vocabulary lists containing blue

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

It appeared extremely blue and was producing X-rays.

From Science Daily Aug. 16, 2026

Particularly revealing are the blue columns, which show what your return would have been if you missed both the indicated number of best days and that same number of worst days.

From MarketWatch Aug. 14, 2026

As with opposition to AI-fueling data centers, the revolt against Flock cameras is drawing support from across the political spectrum, uniting Republicans and Democrats in red and blue America.

From Salon Aug. 14, 2026

In 2018, a Belfast man who was angling caught a blue shark and was bitten while bringing it on board a boat.

From BBC Aug. 13, 2026

They swayed steadily, creaking and clanking, their peculiar watery blue fire casting tides of light over the floor.

From "The Undead Fox of Deadwood Forest" by Aubrey Hartman

Robbie Blue first caught mass attention for choreographing Doechii’s Grammy Awards performance last year, for which he won an Emmy.

From Los Angeles Times Aug. 17, 2026

Blue sharks can reach more than three metres in length and feed in open water on fish, squid, smaller sharks and sea birds.

From BBC Aug. 13, 2026

Hybrids and EVs are generally more expensive than gas-guzzling cars, with the average new EV sales price over $56,000 in June, according to Kelley Blue Book.

From MarketWatch Aug. 13, 2026

My range anxiety when heading for the Blue Ridge Parkway has been reduced to zero.

From The Wall Street Journal Aug. 12, 2026

“That flower in our greenhouse, Natalie, it wasn’t an orchid. Mrs. Menzer gave you a Blue Bearded Iris.”

From "The Science of Breakable Things" by Tae Keller

Researchers have found that, more often than not, the end-of-summer blues lead to stock market weakness.

From MarketWatch Aug. 13, 2026

Mellencamp’s idea for 1996’s “Mr. Happy Go Lucky,” he told Spin that year, was “to take as urban a beat as we could and put it with the most urban ’40s blues we could find.”

From Los Angeles Times Aug. 10, 2026

Jeff Beck was captivated by the sound of American blues artists.

From The Wall Street Journal Jul. 30, 2026

Keep the post-World Cup blues at bay by watching these 15 international series.

From Los Angeles Times Jul. 29, 2026

I guessed I'd resolved the soul and sin thing by lapsing from my heavy-duty Catholic background, giving up my immortal soul for a blues kind of soul.

From "How the García Girls Lost Their Accents" by Julia Alvarez

One entry describes begonia as “a deep pink that is bluer, lighter, and stronger than average coral . . . and bluer and stronger than sweet william—called also gaiety.”

From The Wall Street Journal Mar. 27, 2026

Firstly, they are two to three times as bright as traditional halogens, and their "colour temperature" is bluer and whiter, which mimics natural daylight.

From BBC Feb. 18, 2026

Because the dust blocked shorter, bluer wavelengths, the star’s appearance shifted dramatically toward red.

From Science Daily Oct. 9, 2025

Not everyone supports the flight to bluer skies.

From Science Magazine Nov. 19, 2024

“Wait till you see the flax in bloom. I’ve never been to the sea myself, but I imagine it couldn’t be bluer than a field of flax.”

From "Hattie Big Sky" by Kirby Larson

Once the bluest of blue-chip stocks, IBM’s biggest-ever decline on Tuesday following a profit warning did little to rattle investors focused on a dip in inflation and on AI winners.

From The Wall Street Journal Jul. 15, 2026

His research is the bluest of blue-sky: he uses quantum computers to predict how sub-atomic particles behave.

From BBC Mar. 17, 2026

GameStop is the bluest of blue-chip meme stocks, the Apple or Nvidia of its little world.

From Slate May 13, 2024

The Fontainebleau is the tallest, newest and bluest hotel in southern Nevada’s glittery resort corridor.

From Seattle Times Dec. 12, 2023

Reaching from the cliff face to the far horizon is the bluest, flattest, sweetest sight I’ve ever seen.

From "Without Refuge" by Jane Mitchell

As we talked, the greens blued into ultramarine or yellowed into chartreuse.

From New York Times Feb. 24, 2022

Facebook is the classic example of how the individual investor can get screwed, blued and tattooed.

From Forbes Sep. 1, 2012

Its blued receiver carries extensive engraving, with gold-accented game birds on both sides and the bottom.

From Time Magazine Archive

Winchester Select Midnight The blued receiver carries extensive engraving, with gold-accented game birds on both sides and the bottom.

From Time Magazine Archive

The room blued into view, and I wondered where the night had gone.

From "The Bell Jar" by Sylvia Plath

Wash blue, or blueing, is a laundry product with iron powder and just a hint of blue dye.

From Salon Mar. 17, 2021

The Glen Alden Coal Co. of Buffalo and Rochester, N. Y., has made the last wash a blueing process.

From Time Magazine Archive

This circumstance has led Sociologists Peter and Brigitte Berger to suggest that if what Charles Reich calls "the greening of America" goes on apace, it may shade into a "blueing of America."

From Time Magazine Archive

There were violets, some white, some yellow and some purple, with others blue, like the ones Uncle Wiggily used to make blueing water for Nurse Jane's clothes.

From Uncle Wiggily in the Woods by Howard Roger Garis

You know that you do not put much blueing into a washtub full of water.

From The Golden Censer The duties of to-day, the hopes of the future by John McGovern

The colour actually comes from a process that starts with boiling water and grinding laundry bluing cubes, which are usually used to wash white clothes.

From BBC Feb. 11, 2024

Although Castle made works with color, utilizing a variety of materials that include laundry bluing, watercolor, crayon and even colored ink leached from magazine pages, these are black soot-and-spit.

From Los Angeles Times Aug. 23, 2023

Some on Reddit fixed this by sanding theirs down to take the shine off of the finish, and another recommended using an acrylic topcoat and another chemical bluing.

From The Verge Mar. 9, 2022

When a congressional seat opened up in a bluing stretch of Phoenix’s eastern suburbs, Sinema ran and won.

From Seattle Times Jul. 6, 2021

High above the library’s stained-glass windows and soaring neo-Gothic spires, screeching seagulls whirled in white loops against the slowly bluing sky.

From "The Boys in the Boat: Nine Americans and Their Epic Quest for Gold at the 1936 Berlin Olympics" by Daniel James Brown

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