Pronunciation : At"mo
Part of Speech : n.
Etymology : [Contr. fr. atmosphere.] (Physics)
Definition : Defn: The standard atmospheric pressure used in certain physical measurements calculations; conventionally, that pressure under which the barometer stands at 760 millimeters, at a temperature of 0? Centigrade, at the level of the sea, and in the latitude of Paris. Sir W. Thomson.
Source : Webster's Unabridged Dictionary, 1913