what is psi

PSI stands for "pound per square inch," which is a unit of measurement for pressure or stress based on avoirdupois units. It is the pressure resulting from a force with a magnitude of one pound-force applied to an area of one square inch. In the metric system, 1 psi is approximately equal to 6.895 kilopascals. This unit is commonly used to measure the pressure of gases (pneumatic pressure) or liquids (hydraulic pressure) and is also used to measure tensile strength and elastic modulus strength of materials