hydraulic

IPA/haɪˈdrɒlɪk/
KK[haɪdrˈɔlɪk]IPA/haɪˈdrɔːlɪk/

hydraulic — adjective

  • hydraulicpositive
  • more hydrauliccomparative
  • most hydraulicsuperlative

1. using the force of liquid that moves under pressure through pipes or tubes to ma

1.adjectiveB2
Definition

using the force of liquid that moves under pressure through pipes or tubes to make a machine or piece of equipment work

Example

The hydraulic lift raised Zuri's car so she could inspect the brakes.

attributive: hydraulic + lift — equipment powered by liquid pressure

Aarav used a hydraulic jack to lift the corner of the old wooden shed.

hydraulic jack — tool for lifting heavy objects

Common collocations
  • hydraulic fluid
  • hydraulic pressure
  • hydraulic brake
  • hydraulic lift
  • hydraulic jack
  • hydraulic press
  • hydraulic pump
  • hydraulic cylinder
Synonyms
  • fluid-powered

    broader term covering both hydraulic (liquid) and pneumatic (air) systems

  • liquid-operated

    more descriptive; less common in technical writing but clearer for learners

Antonyms
  • manual

    operated by human effort rather than liquid pressure

  • pneumatic

    operated by compressed air or gas rather than liquid

Grammar Patterns

hydraulic + noun (machine/equipment)

Usage Note

Nearly always appears before a noun that names a type of machine, tool, or system. The liquid used is usually oil, not water, despite the Greek root meaning 'water'.

Common Mistakes

The factory doors open with a hydraulic system that uses compressed air.
The factory doors open with a pneumatic system that uses compressed air.
'hydraulic' means powered by liquid under pressure; 'pneumatic' means powered by compressed air or gas.

2. relating to the science that studies how liquids behave under pressure and how t

2.adjectiveC1
Definition

relating to the science that studies how liquids behave under pressure and how their force can be used in machines and equipment

Example

Harper studied hydraulic engineering at a university in southern Taiwan.

collocation: hydraulic engineering — branch of engineering

Élise gave a presentation on hydraulic systems at the science fair.

Common collocations
  • hydraulic system
  • hydraulic engineering
  • hydraulic principle
  • hydraulic power
  • hydraulic equipment
  • hydraulic design
Synonyms
  • fluid-mechanical

    more specific; used in academic contexts to describe the study of fluid mechanics applied to machinery

Grammar Patterns

hydraulic + noun (system/engineering/principle)

Usage Note

Frequently appears with academic or technical nouns such as system, engineering, principle, and power. Less common than sense 1 in everyday speech; most often found in textbooks, university courses, and technical manuals.

Common Mistakes

This car has a hydraulic engine.
This car has a hydraulic braking system.
engines are rarely called 'hydraulic'; the word typically describes systems, pumps, or components that use liquid pressure.

Word family

  • hydraulics
    nounC1
  • hydraulically
    adverbC1

Synonym discussion

Sense: adjective/1

The choice among these four depends on how equipment is powered. Hydraulic systems use liquid under pressure (usually oil), which does not compress, making them ideal for heavy lifting — excavator arms and car lifts are typical examples. Pneumatic systems use compressed air or gas; they are lighter and cleaner but deliver less force for the same size. Mechanical systems rely on gears, belts, and levers — direct physical connections without any fluid. Electric systems use motors and batteries; they are quiet and efficient but may lack the raw power of hydraulics for very heavy loads. For instance, a bicycle can have mechanical cable brakes, hydraulic disc brakes, or electric regenerative brakes, each working differently even though they perform the same stopping function.

hydraulic ↗pneumaticmechanical ↗electric ↗

Etymology

GreekLatinFrenchEnglish

The word hydraulic comes from the Greek words hydor (water) and aulos (pipe or tube). It entered English through Latin hydraulicus and French hydraulique. The original meaning was strictly about water moving through pipes, but over time the term expanded to cover any liquid (especially oil) used under pressure in machinery.