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  1. Air | Composition, Oxygen, Nitrogen | Britannica

    Air, mixture of gases comprising the Earth’s atmosphere. The mixture contains a group of gases of nearly constant concentrations and a group with concentrations that are variable in both …

  2. Air - National Geographic Society

    Oct 1, 2024 · Air is the invisible mixture of gases that surrounds Earth. Air contains important substances, such as oxygen and nitrogen, that most species need to survive.

  3. AIR Definition & Meaning - Merriam-Webster

    The meaning of AIR is the mixture of invisible odorless tasteless gases (such as nitrogen and oxygen) that surrounds the earth; also : the equivalent mix of gases on another celestial object …

  4. Air - Simple English Wikipedia, the free encyclopedia

    Air is a mixture of many gases and tiny dust particles. It is the clear gas in which living things live and breathe. It has an indefinite shape and volume. It has mass and weight, because it is …

  5. The Chemical Composition of Air - ThoughtCo

    Jul 29, 2024 · Nearly all of Earth's atmosphere (air) is comprised of a mere five gases: nitrogen, oxygen, water vapor, argon, and carbon dioxide. Several other compounds are also present in …

  6. What's in the Air? - Center for Science Education

    Air is a mixture of gases, most of which are naturally occurring. Air also contains a significant amount of human-made air pollutants, including some that are not safe to breathe and some …

  7. AIR | definition in the Cambridge English Dictionary

    AIR meaning: 1. the mixture of gases that surrounds the earth and that we breathe: 2. the space above the…. Learn more.

  8. Air Mass/Density | NASA Earthdata

    Sep 30, 2025 · Pure, dry air has a density of 1.293 kg m−3 at a temperature of 273 K and a pressure of 101.325 kPa. Apart from the variability of water vapor, the composition of air is …

  9. Air Definition & Meaning | YourDictionary

    Air definition: An atmospheric movement; a breeze or wind.

  10. AIR Definition & Meaning | Dictionary.com

    The terms air or the air is used generally to refer to the sky or open space outside. Real-life example: Airplanes and helicopters are designed to fly in the air, meaning the empty space …