The envelope of gases surrounding the earth or another planet. The atmosphere of Earth is composed mainly of nitrogen and oxygen.
The pervading tone or mood of a place, situation, or work of art. The restaurant had a cozy atmosphere that made diners feel at home.
A unit of pressure equal to the pressure exerted by a column of mercury 760 mm high at sea level and at 0 degrees Celsius. The pressure in the chamber was measured at one atmosphere.