hydraulic

adjective

hy·​drau·​lic hī-ˈdrȯ-lik 

1

: operated, moved, or effected by means of water

2

a

: of or relating to hydraulics

hydraulic engineer

b

: of or relating to water or other liquid in motion

hydraulic erosion

3

: operated by the resistance offered or the pressure transmitted when a quantity of liquid (such as water or oil) is forced through a comparatively small orifice or through a tube

hydraulic brakes

4

: hardening or setting under water

hydraulic cement

hydraulically

hī-ˈdrȯ-li-k(ə-)lē 

adverb

Did you know?

By means of a hydraulic lift, the driver can lift the bed of a dump truck with the touch of a button. He might also repair the hydraulic steering, the hydraulic brake, or the hydraulic clutch—all of which, like the lift that holds everything up, take advantage of the way liquids act under pressure. Somewhat like a pulley or a lever, a hydraulic system magnifies the effect of moderate pressure exerted over a longer distance into powerful energy for a shorter distance.

Examples of hydraulic in a Sentence

Recent Examples on the Web

Unlike commercial light-water reactors that operate under heavy hydraulic pressure, each 55-megawatt SEALER unit uses molten lead as its primary cooling fluid. — Aman Tripathi, Interesting Engineering, 26 Aug. 2026

The bike weighs 106 lb (48 kg), rolls on 14-inch front and 12-inch rear tires, and comes with hydraulic disc brakes. — New Atlas, 26 Aug. 2026

Two other reports for 2026 were added in the past few days, MIOSHA said a 28-year-old landscaper in Southfield was working underneath a compact wheel loader to repair a hydraulic line on the vehicle on January 16. — Paula Wethington, CBS News, 19 Aug. 2026

Authorities said equipment found at the ADU included hydraulic presses, cutting agents, personal protective equipment, scales and Narcan, a medication used to counteract the effects of opioids. — Jason Green, Mercury News, 18 Aug. 2026

Word History

Etymology

Latin hydraulicus, from Greek hydraulikos, from hydraulis hydraulic organ, from hydr- + aulos reed instrument — more at alveolus

First Known Use

1661, in the meaning defined at sense 1

Phrases Containing hydraulic

• hydraulic fracturing

Rhymes for hydraulic

• bucolic
• carbolic
• embolic
• glycolic
• phenolic
• podzolic
• symbolic
• systolic
• alcoholic
• anabolic
• apostolic
• catabolic

Kids Definition

hydraulic

adjective

hy·​drau·​lic hī-ˈdrȯ-lik 

1

: operated, moved, or brought about by means of water

2

: of or relating to hydraulics

hydraulic engineer

3

: operated by pressure transmitted when a quantity of liquid is forced through a small hole or through a tube

hydraulic brakes

4

: hardening or setting under water

hydraulic cement

hydraulically

-ˈdrȯ-li-k(ə-)lē 

adverb