atmosphere

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. The gaseous mass or envelope surrounding a celestial body, especially the one surrounding the earth, and retained by the celestial body's gravitational field.
2. n. The air or climate in a specific place.
3. n. Physics A unit of pressure equal to the air 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). See Table at measurement.
4. n. A dominant intellectual or emotional environment or attitude: an atmosphere of distrust among the electorate.
5. n. The dominant tone or mood of a work of art.
6. n. An aesthetic quality or effect, especially a distinctive and pleasing one, associated with a particular place: a restaurant with an Old World atmosphere.

Century Dictionary and Cyclopedia

1. n. The aëriform fluid which surrounds the earth, and extends to an undetermined height above its surface; the air. It is a mechanical mixture of 79 parts by volume of nitrogen and 21 of oxygen, with a trace of carbon dioxid and a variable quantity of aqueous vapor, ammonia, ozone, and organic matter. The composition of the normal atmosphere varies but slightly in different localities, although near towns it usually contains impurities, such as sulphuric acid, hydrochloric acid, etc. The movements of the atmosphere constitute the winds, and in it are formed or produced clouds, rain, and snow. Its density is greatest at the earth's surface, and decreases as the height above the earth increases. The atmosphere, like other bodies, gravitates toward the earth, and therefore has weight and exerts pressure. Its average weight at the level of the sea is about 15 pounds (14.7) to the square inch.
2. n. A conventional unit of atmospheric pressure. An atmosphere is in English use the pressure of a vertical column of 30 inches of mercury at the freezing-point at London; in French use it is the pressure of 760 millimeters of mercury at the freezing-point at Paris. For the absolute atmosphere in the C. G. S. (centimeter-gram-second) system, see absolute. The weight of the atmosphere to the square inch is commonly employed as a convenient unit for pressures arising from other causes, such as the weight of liquids, the force of steam, etc.: thus, a pressure in a steam-boiler of 3 atmospheres means a pressure equal to 45 pounds per square inch.
3. n. The gaseous envelop surrounding any of the heavenly bodies.
4. n. Any gaseous medium: as, “an atmosphere of cold oxygen,” Miller.
5. n. An assumed outer envelop of force, effluvia, etc., surrounding a body: as, an electrical atmosphere.
6. n. Figuratively, intellectual or moral environment; pervading influence.

Wiktionary

1. n. The gases surrounding the Earth or any astronomical body.
2. n. The air in a particular place.
3. n. The mood or feeling in a situation.
4. n. A unit of measurement for pressure (symbol: atm)

GNU Webster's 1913

1. n. The whole mass of aëriform fluid surrounding the earth; -- applied also to the gaseous envelope of any celestial orb, or other body.
2. n. Any gaseous envelope or medium.
3. n. A supposed medium around various bodies.
4. n. The pressure or weight of the air at the sea level, on a unit of surface, or about 14.7 lbs. to the sq. inch.
5. n. Any surrounding or pervading influence or condition.
6. n. The portion of air in any locality, or affected by a special physical or sanitary condition

WordNet 3.0

1. n. the mass of air surrounding the Earth
2. n. a distinctive but intangible quality surrounding a person or thing
3. n. a particular environment or surrounding influence
4. n. the envelope of gases surrounding any celestial body
5. n. the weather or climate at some place
6. n. a unit of pressure: the pressure that will support a column of mercury 760 mm high at sea level and 0 degrees centigrade