pressure
A scalar physical quantity defined as the force exerted per unit of surface area. It measures the deforming effect (compressions and expansions in the case of a fluid such as air) or the penetrating capacity of a force. The unit in which it is expressed in the International System is the pascal (Pa), which is equal to the pressure exerted by a force of one newton (N) over one square meter (m2) [1 Pa = 1 N/m2]. Atmospheric pressure is one of the most important meteorological variables.