Definition of: atmosphere

(at′məs·fir) noun
1. The mass or body of gases that surrounds the earth or any heavenly body.
2. The particular climatic condition of any place or region regarded as dependent on the air.
3. Any surrounding or pervasive element or influence: an atmosphere of gloom.
4. The prevailing tone of a poem, novel, painting, etc.
5. Colloq. An indefinable aura regarded as especially characteristic: This café has atmosphere.
6. Physics A conventional unit of pressure, the equivalent of the weight of a column of mercury 1 centimeter in diameter and 29.92 inches high at sea level, at a temperature of 0° C.: one atmosphere equals a pressure of 14.69 pounds per square inch. [<NL atmosphaera <Gk. atmos vapor + sphaira sphere]