Pressure
Pressure (symbol: "p" or "P") is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled "gage" pressure) is the pressure relative to the ambient pressure.

Various units are used to express pressure. Some of these derive from a unit of force divided by a unit of area; the SI unit of pressure, the pascal (Pa), for example, is one newton per square metre (N/m2); similarly, the pound-force per square inch (psi) is the traditional unit of pressure in the imperial and U.S. customary systems. Pressure may also be expressed in terms of standard atmospheric pressure; the atmosphere (atm) is equal to this pressure, and the torr is defined as of this. Manometric units such as the centimetre of water, millimetre of mercury, and inch of mercury are used to express pressures in terms of the height of column of a particular fluid in a manometer.
Q11402
force
Concept
Q11500
area
Concept
Q7424019
Gauge pressure
Concept
None
units
UNK
Q12457
SI
Concept
Q44395
pascal
Concept
Q12438
newton
Concept
Q25343
square metre
Concept
Q1194225
pound-force
Concept
Q1063786
square inch
Concept
Q626299
psi
Concept
Q641227
imperial
Concept
Q1116609
U.S. customary
Concept
Q177974
standard atmospheric pressure
Concept
Q177974
atmosphere
Concept
Q185648
torr
Concept
Q103451781
centimetre of water
UNK
Q6859652
millimetre of mercury
Concept
Q1050958
inch of mercury
Concept
None
column of a particular fluid
UNK
Q39552
Pressure
Concept
Q39552
Pressure
Concept
+2^^http://www.w3.org/2001/XMLSchema#decimal
2
NUMBER
measured physical quantity
measured physical quantity
measured physical quantity