from The American Heritage® Dictionary of the English Language, 5th Edition.

  • adjective Neither warm nor very cold; moderately cold.
  • adjective Giving or suggesting relief from heat.
  • adjective Marked by calm self-control.
  • adjective Marked by indifference, disdain, or dislike; unfriendly or unresponsive.
  • adjective Of, relating to, or characteristic of colors, such as blue and green, that produce the impression of coolness.
  • adjective Knowledgeable or aware of the latest trends or developments.
  • adjective Excellent; first-rate.
  • adjective Acceptable; satisfactory.
  • adjective Slang Entire; full.
  • adverb Informal In a casual manner; nonchalantly.
  • intransitive verb To make less warm.
  • intransitive verb To make less ardent, intense, or zealous.
  • intransitive verb Physics To reduce the molecular or kinetic energy of (an object).
  • intransitive verb To become less warm.
  • intransitive verb To become calmer.
  • noun A cool place, part, or time.
  • noun The state or quality of being cool.
  • noun Composure; poise.
  • idiom (cool it) To calm down; relax.
  • idiom (cool it) To stop doing something.
  • idiom (cool (one's) heels) To wait or be kept waiting.

from The Century Dictionary.

  • Moderately cold; being of a temperature neither warm nor very cold: as, cool air; cool water.
  • Having a slight or not intense sensation of cold. See cold, a., 3.
  • Not producing heat or warmth; permitting or imparting a sensation of coolness; allowing coolness, especially by facilitating radiation of heat or access of cool air, or by intercepting radiated heat: as, a cool dress.
  • In figurative uses:
  • Not excited or heated by passion of any kind; without ardor or visible emotion; calm; unmoved: as, a cool temper; a cool lover.
  • Not hasty; deliberate: as, a cool purpose.
  • Manifesting coldness, apathy, or dislike; chilling; frigid: as, a cool manner.
  • Quietly impudent, defiant, or selfish; deliberately presuming: said of persons and acts.
  • Absolute; without qualification; round: used in speaking of a sum of money, generally a large sum, by way of emphasizing the amount.
  • Unconcerned, lukewarm, indifferent; cold-blooded, repellent
  • In painting, to strengthen (colors) on the blue and violet side of the spectrum, or to reduce (reds and yellows).
  • noun A moderate or refreshing state of cold; moderate temperature of the air between hot and cold.
  • To make cool or cold; reduce the temperature of: as, ice cools water.
  • To allay the warmth or heated feeling of; impart a sensation of coolness to; cause to feel cool.
  • To abate the ardor or intensity of; allay, as passion or strong emotion of any kind; calm, as anger; moderate, as desire, zeal, or ardor; render indifferent.
  • To mitigate.
  • To become cool; become less hot; lose heat.
  • To lose the heat of excitement, passion, or emotion; become less ardent, angry, zealous, affectionate, etc.; become more moderate.
  • noun An obsolete spelling of cole.

from the GNU version of the Collaborative International Dictionary of English.

  • intransitive verb To become less hot; to lose heat.
  • intransitive verb To lose the heat of excitement or passion; to become more moderate.
  • transitive verb To make cool or cold; to reduce the temperature of.
  • transitive verb To moderate the heat or excitement of; to allay, as passion of any kind; to calm; to moderate.
  • transitive verb [Colloq.] to dance attendance; to wait, as for admission to a patron's house.
  • adjective Moderately cold; between warm and cold; lacking in warmth; producing or promoting coolness.
  • adjective Not ardent, warm, fond, or passionate; not hasty; deliberate; exercising self-control; self-possessed; dispassionate; indifferent.
  • adjective Not retaining heat; light.
  • adjective Manifesting coldness or dislike; chilling; apathetic.


from The American Heritage® Dictionary of the English Language, 4th Edition

[Middle English cole, from Old English cōl; see gel- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English, from Old English cōl ("cool, cold, tranquil, calm"), from Proto-Germanic *kōlaz, *kōlijaz (“cool”), from Proto-Indo-European *gelǝ- (“cold”). Cognate with Dutch koel ("cool"), German kühl ("cool"). Related to cold.

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Middle English colen, from Old English cōlian ("to cool, grow cold, be cold"), from Proto-Germanic *kōlēnan (“to become cold”), from Proto-Indo-European *gel- (“to freeze”). Cognate with Dutch koelen ("to cool"), German kühlen ("to cool"), Swedish, häftig ("cool")kyla ("to cool, refrigerate"). Also partially from Middle English kelen, from Old English cēlan ("to cool, be cold, become cold"), from Proto-Germanic *kōlijanan (“to cool”), altered to resemble the adjective cool. See keel.


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  • Who defines cool?

    I do.

    January 22, 2007

  • Hard to argue with that Tank.

    January 22, 2007

  • Arrogance, like stupidity, is always difficult to argue with.

    February 1, 2007

  • A contranym: both good and bad.

    May 15, 2008

  • Daddy and Mummy lay in the gras by the streem and I played round about and had oranj juse then Mummy and daddy has some wine that was cooling in the streem.

    - Peter Reading, C, 1984

    July 23, 2008

  • Cool as a cucumber.

    August 3, 2008

  • According to an NPR piece I heard today, Lester Young, the great saxophonist coined the slang usage of the word "cool" as a culturally favorable adjective. Also, "bread" to mean money.

    August 28, 2009

  • Im cool.

    March 30, 2010