Definition

1. Verb:
   • To increase the pressure in or of a container or space: To raise the internal pressure of a closed system, such as an aircraft cabin or a gas cylinder, above the external ambient pressure.
   • To maintain a certain pressure: To keep the pressure within a system at a specific, often higher-than-ambient, level.
   • To subject to high pressure: To apply physical force per unit area to a gas or liquid.

Usage and Examples

• Verb:
  • The engineers will pressurise the fuel tank before the test. (They will increase the pressure inside the tank.)
  • Modern aircraft cabins are pressurised to simulate conditions at a lower altitude. (They are maintained at a specific, comfortable air pressure.)
  • The machine pressurises the hydraulic fluid to operate the brakes. (It increases the pressure on the liquid.)

Advanced Usage

• "To pressurise someone": (Common variant: pressurize) To coerce or attempt to compel someone into doing something.
  • He felt pressurised by his peers to conform. (He felt coerced by social pressure.)
• Used in technical and scientific contexts to describe the state of a system.
  • The experiment requires a pressurised environment.

Variants and Related Words

• Pressurize (verb): The standard spelling, especially in American English. It shares all definitions with 'pressurise'.
• Pressurisation / Pressurization (noun): The act or process of increasing or maintaining pressure.
  • Cabin pressurisation is essential for high-altitude flight.
• Pressurised / Pressurized (adjective): Describing something that is under pressure.
  • A pressurised water reactor.
• De-pressurise / Depressurize (verb): To release or reduce pressure.

Synonyms

• Compress: To reduce in volume by pressure (often for solids/gases).
• Pump up: To inflate or increase pressure (informal, e.g., for tyres).

Related Phrasal Verbs/Constructions

• To pressurise into (doing something): To use influence or arguments to force someone into an action.
  • They tried to pressurise him into signing the contract.

Notes on Meaning

• The primary technical meaning relates to physical pressure within enclosed systems (engineering, aviation, diving).
• The secondary, figurative meaning (to coerce) is very common in general language. In this sense, it is synonymous with (as a verb). The spelling 'pressurize' is more frequent for this figurative use.

Verb

1. increase the pressure in or of
   • The captain will pressurize the cabin for the passengers' comfort
2. maintain a certain pressure
   • the airplane cabin is pressurized
   • pressurize a space suit
3. increase the pressure on a gas or liquid