Final answer:
PSIA stands for (1) Pounds per Square Inch Absolute, a unit of pressure that includes atmospheric pressure in addition to the measured gauge pressure.
Step-by-step explanation:
PSIA stands for Pounds per Square Inch Absolute, which is a unit of pressure measurement. This term refers to the absolute pressure within a system, which is the sum of the gauge pressure and the atmospheric pressure outside of the system. Gauge pressure, on the other hand, is the pressure measured relative to atmospheric pressure, and does not include the atmospheric pressure itself.
For example, if a tire gauge reads 34 psi, this is the gauge pressure. The absolute pressure would be 34 psi plus the atmospheric pressure (usually around 14.7 psi at sea level), totaling to 48.7 psi. The accurate measurement of pressure is essential in various scientific and industrial applications, such as checking tire pressure, measuring blood pressure, or in meteorological data.