Gas pressure is defined as a the force of when it pushes out, and when its divided by the area of whatever it is in.
Absolute
blowdown pressure is defined as the difference between set pressure and re-seat pressure
Pressure is defined as force per area
Pressure is a force defined as a push that acts over a certain area.
Usually we use a temperature of 20 °C and an absolute pressure of 101.325 kPa for 1 atmosphere.
Standard conditions, or standard temperature and pressure (STP) is the atmospheric pressure at sea level with temperature at zero degrees Celsius (273.15 Kelvin).
Pressure is the force measured over an area
Pressure is defined as the force per unit area applied in a direction perpendicular to the surface. The standard unit of pressure is the pascal (Pa). This did not answer my question on how pressure is used.
Pressure is defined as the force per area.
Gas pressure is defined as the force exerted by gas molecules on the walls of their container. Factors that influence the measurement of gas pressure include the number of gas molecules present, the volume of the container, and the temperature of the gas.
There is no pressure against a vacuum since a vacuum is defined as a space devoid of matter and therefore no gas molecules to exert pressure.
The term you're looking for is "standard atmospheric pressure," which is defined as the atmospheric pressure at sea level at zero degrees Celsius. It is commonly used as a reference point for pressure measurements in meteorology and other fields.