1. The gaseous mass or envelope surrounding a celestial body, especially the one surrounding the earth, and rened by the celestial body's gravitational field.

2. Ther or climate in a specific place.

3. Abbr. atmPhysics A unit of pressure equal to ther pressure at sea level. It equals the amount of pressure that will support a column of mercury 760 millimeters high at 0 degrees Celsius under standard gravity, or 14.7 pounds per square inch (1.01325 × 10⁵ pascals).

4. A dominant intellectual or emotional environment or attitude:an atmosphere of distrust among the electorate.

5. The dominant tone or mood of a work of art.

6. An aesthetic quality or effect, especially a distinctive and pleasing one, associated with a particular place:a restaurant with an Old World atmosphere.