Abbreviation indicating that a gas volume has been expressed as if it were at standard temperature (0°C), standard pressure (760 mm Hg absolute), and dry; under these conditions a mole of gas occupies 22.4 L.
* * *
short time Page distribution
* * *
standard temperature and pressure, dry; denoting a volume of dry gas at 0° C and a pressure of 760 mm Hg.Medical dictionary. 2011.