pressure
PRESH-er
/ˈpreʃ.ər/
The continuous physical force exerted per unit area upon an object or pipe wall by a fluid.
In fluid mechanics, pressure represents potential energy stored within contained liquids or gases.
The story behind the word. Derived from Latin 'pressura', from 'premere' meaning 'to press'. In physics and fluid mechanics, Blaise Pascal helped define fluid pressure mathematically in the 17th century, leading to the unit 'Pascal'.
Word relationships
- head: Head refers specifically to fluid pressure caused by height/elevation difference, whereas pressure is force per unit area.
- tension: Tension is a pulling force, whereas pressure is a pushing force perpendicular to internal pipe surfaces.
- vacuum: A vacuum is a condition of pressure below ambient atmospheric pressure.
Commonly confused with
- flow rate: Pressure is force per unit area (PSI/Bar); flow rate is volume of fluid moving past a point per unit time (GPM/LPM).
Word family
- pressurize (verb): To bring fluid or container to a specific internal pressure.
Collocations
- water pressure
- pressure drop
- pressure gauge
- high pressure
- pressure relief valve
Idioms & expressions
- under pressure (feeling stressed or forced)
- cooker pressure (intense situation)
Example sentences
- "The pipefitter installed a digital pressure gauge to verify that the domestic water main maintained sixty pounds per square inch." System testing
- "Excessive steam pressure inside the boiler triggered the emergency relief valve to open automatically." Safety engineering
Memory hook
PRESSURE PRESSES outwards against the pipe walls. Force exerted on walls.
When not to use
Do not confuse flow rate (volume per minute) with pressure (force per square inch).
Fun facts
- Water pressure increases by approximately 0.433 pounds per square inch (PSI) for every single foot of vertical water column height!
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