Merriam-Webster Logo
  • Dictionary
  • Thesaurus
  • Scrabble
  • Spanish Central
  • Learner's Dictionary


noun, often attributive \ˈer\

Simple Definition of air

  • : the invisible mixture of gases (such as nitrogen and oxygen) that surrounds the Earth and that people and animals breathe

  • : the space or sky that is filled with air

  • : methods of travel that involve flying

Source: Merriam-Webster's Learner's Dictionary

Full Definition of air

  1. 1 a archaic :  breath b :  the mixture of invisible odorless tasteless gases (as nitrogen and oxygen) that surrounds the earth c :  a light breeze

  2. 2 a :  empty space b :  nothingness <vanished into thin air> c :  a sudden severance of relations <she gave me the air>

  3. 3 [probably translation of Italian aria] a :  tune, melody b Elizabethan & Jacobean music :  an accompanied song or melody in usually strophic form c :  the chief voice part or melody in choral music

  4. 4 a :  outward appearance of a thing <an air of luxury> b :  a surrounding or pervading influence :  atmosphere <an air of mystery> c :  the look, appearance, or bearing of a person especially as expressive of some personal quality or emotion :  demeanor <an air of dignity> d :  an artificial or affected manner <put on airs>

  5. 5 :  public utterance <he gave air to his opinion>

  6. 6 :  compressed air

  7. 7 a (1) :  aircraft <go by air> (2) :  aviation <air safety> <air rights> (3) :  air force <air headquarters> b (1) :  the medium of transmission of radio waves; also :  radio, television <went on the air> (2) :  airtime

  8. 8 :  a football offense utilizing primarily the forward pass <trailing by 20 points, the team took to the air>

  9. 9 :  an air-conditioning system

  10. 10 :  the height achieved in performing an aerial maneuver <a snowboarder catching big air>; also :  the maneuver itself


play \-ləs\ adjective



in the air

  1. :  in wide circulation :  about

up in the air

  1. :  not yet settled

Examples of air in a sentence

  1. These laws are meant to produce cleaner air.

  2. A delicious smell filled the air.

  3. I like to dine outdoors in the open air.

  4. He can't breathe! Everybody move back and give him some air!

  5. High in the mountains the air is thin and it can be hard to breathe.

  6. He pumped air into the bicycle tire.

  7. The city is wonderful seen from the air.

  8. the fish of the sea and the birds of the air

  9. The balloon rose up into the air and then floated through the air.

  10. There has been heavy fighting on the ground and in the air.

Origin and Etymology of air

Middle English, from Anglo-French, from Latin aer, from Greek aēr

First Known Use: 14th century

Synonym Discussion of air

pose, air, airs, affectation, mannerism mean an adopted way of speaking or behaving. pose implies an attitude deliberately assumed in order to impress others <her shyness was just a pose>. air may suggest natural acquirement through environment or way of life <a traveler's sophisticated air>. airs always implies artificiality and pretentiousness <snobbish airs>. affectation applies to a trick of speech or behavior that strikes the observer as insincere <the posh accent is an affectation>. mannerism applies to an acquired eccentricity that has become a habit <gesturing with a cigarette was her most noticeable mannerism>.

Other Climate/Meteorology Terms




Simple Definition of air

  • : to place something in an open area where there is a lot of moving air to make it cool, dry, or clean

  • : to allow air from the outside to enter something (such as a room) so that it becomes fresher or cleaner

  • : to make (something) known in public : to state (something) publicly

Source: Merriam-Webster's Learner's Dictionary

Full Definition of air

  1. transitive verb
  2. 1 :  to expose to the air for drying, purifying, or refreshing :  ventilate —often used with out

  3. 2 :  to expose to public view or bring to public notice

  4. 3 :  to transmit by radio or television <air a program>

  5. intransitive verb
  6. 1 :  to become exposed to the open air

  7. 2 :  to become broadcast <the program airs daily>

Examples of air in a sentence

  1. The blankets were left outside to air.

  2. She opened the windows to air the room.

  3. The company had a meeting so that employees could air their complaints.

  4. The interview will be aired tomorrow.

  5. The interview will air tomorrow.


First Known Use of air


Synonym Discussion of air

express, vent, utter, voice, broach, air mean to make known what one thinks or feels. express suggests an impulse to reveal in words, gestures, actions, or what one creates or produces <expressed her feelings in music>. vent stresses a strong inner compulsion to express especially in words <a tirade venting his frustration>. utter implies the use of the voice not necessarily in articulate speech <utter a groan>. voice does not necessarily imply vocal utterance but does imply expression or formulation in words <an editorial voicing their concerns>. broach adds the implication of disclosing for the first time something long thought over or reserved for a suitable occasion <broached the subject of a divorce>. air implies an exposing or parading of one's views often in order to gain relief or sympathy or attention <publicly airing their differences>.

AIR Defined for Kids



noun \ˈer\

Definition of air for Students

  1. 1 :  the invisible mixture of odorless tasteless gases that surrounds the earth

  2. 2 :  the space or sky that is filled with air <The balloon rose up into the air.>

  3. 3 :  air that is compressed <I filled the car's tires with air.>

  4. 4 :  outward appearance :  a quality that a person or thing has <He has an air of mystery about him.>

  5. 5 :  aircraft <travel by air>

  6. 6 :  aviation 1

  7. 7 :  a radio or television broadcast <He gave a speech on the air.>

  8. 8 airs plural :  an artificial way of acting <put on airs>




Definition of air for Students



  1. 1 :  to place in the air for cooling, freshening, or cleaning <air blankets>

  2. 2 :  to make known in public <air complaints>

Medical Dictionary


noun \ˈa(ə)r, ˈe(ə)r\

Medical Definition of air

  1. :  a mixture of invisible odorless tasteless sound-transmitting gases that is composed by volume chiefly of 78 percent nitrogen, 21 percent oxygen, 0.9 percent argon, 0.03 percent carbon dioxide, varying amounts of water vapor, and minute amounts of rare gases (as helium), that surrounds the earth with half its mass within four miles of the earth's surface, that has a pressure at sea level of about 14.7 pounds per square inch, and that has a density of 1.293 grams per liter at 0°C and 760 mm pressure

Seen and Heard

What made you want to look up air? Please tell us where you read or heard it (including the quote, if possible).


looking or feeling very sad

Get Word of the Day daily email!


Take a 3-minute break and test your skills!


Which is a synonym of asperse?

beat placate defame divulge
Name That Thing

Test your visual vocabulary with our 10-question challenge!


Test Your Knowledge - and learn some interesting things along the way.