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  1. 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 …

  2. Air | Composition, Oxygen, Nitrogen | Britannica

    Sep 12, 2025 · 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 …

  3. Home | American Institutes for Research

    AIR applies its decades of workforce research in developing the knowledge, tools, systems, and programs needed to maximize human and organizational potential in the 21st century.

  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. 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.

  6. AIR | English meaning - Cambridge Dictionary

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

  7. 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 …

  8. What is the definition of air? - The Institute for Environmental ...

    Jun 19, 2025 · Air is the mixture of gases surrounding the Earth. Wind is simply air in motion, typically caused by differences in air pressure due to uneven heating of the Earth’s surface.

  9. 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 …

  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 …