Definition : The pressure at a point in a fluid in hydrostatic equilibrium is defined as the normal force per unit area exerted by the fluid on a surface of infinitesimal area containing the point.
Thus, the pressure, p = limΔA→0 \(\frac{F}{ΔA}\) where F is the magnitude of the normal force on a surface of area ∆A. The pressure is defined to be a scalar quantity.
SI unit: the pascal (Pa), 1 Pa = 1 N∙m-2 CGS unit: the dyne per square centimetre (dyn/cm2)
Dimensions : [p] = [F][A-1] = [MLT-2 , L-2] = [ML-1T-2]