Hydraulics is a topic in engineering dealing with the mechanical properties of liquids.

Hydraulic may also refer to:

Business

• London Hydraulic Power Company, a London, England power company, closed in 1977

Engineering

• Hydraulic circuit, a system comprising an interconnected set of discrete components that transport liquid
• Hydraulic diameter, a commonly used term when handling flow in non-circular tubes and channels
• Hydraulic engineering, a sub-discipline of civil engineering is concerned with the flow and conveyance of fluids, principally water and sewage
• Hydraulic fracturing, a well-stimulation technique in which rock is fractured by a pressurized liquid
  • Hydraulic fracturing by country
• Hydraulic intensifier, a hydraulic machine for transforming hydraulic power at low pressure into a reduced volume at higher pressure
• Hydraulic jump, a phenomenon frequently observed in rivers and spillways, when liquid at high velocity discharges into a zone of lower velocity, and a rather abrupt rise occurs in the liquid surface
• Hydraulic mining, a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment
• Hydraulic power, disambiguation page
• Hydraulic power network, a system of interconnected pipes carrying pressurized liquid used to transmit mechanical power from a power source, like a pump, to hydraulic equipment like lifts or motors
• Hydraulic resistance, disambiguation page
• Hydraulic transmission, disambiguation page
• Hydropower, hydraulic energy

Equipment

• Breaker (hydraulic), a powerful percussion hammer fitted to an excavator for demolishing concrete structures or rocks
• Electro-hydraulic systems, used for power steering
• Hydraulic accumulator, a pressure storage reservoir in which a non-compressible hydraulic fluid is held under pressure by an external source
• Hydraulic brake, an arrangement of braking mechanism which uses brake fluid, typically containing ethylene glycol, to transfer pressure from the controlling mechanism to the braking mechanism
• Hydraulic cement, cement distinguished by its reactivity with water, versus carbon dioxide
• Hydraulic cylinder, (also called a linear hydraulic motor) is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke
• Hydraulic debarker, a machine removing bark from wooden logs by the use of water under pressure
• Hydraulic drive system, a drive or transmission system that uses pressurized hydraulic fluid to power hydraulic machinery
• Hydraulic fill, an embankment or other fill in which the materials are deposited in place by a flowing stream of water
• Hydraulic fluid, the medium by which power is transferred in hydraulic machinery
• Hydraulic head, or piezometric head is a specific measurement of liquid pressure above a geodetic datum
• Hydraulic lift, a type of hydraulic machinery or a form of hydraulic redistribution, a plant root phenomenon
• Hydraulic lime, a general term for varieties of lime (calcium oxide), or slaked lime (calcium hydroxide), used to make lime mortar which set through hydration: thus they are called hydraulic
• Hydraulic machinery, machinery and tools that use liquid fluid power to do simple work. Heavy equipment is a common example
• Hydraulic manifold, a manifold that regulates fluid flow between pumps and actuators and other components in a hydraulic system
• Hydraulic motor, a mechanical actuator that converts hydraulic pressure and flow into torque and angular displacement (rotation)
• Hydraulic press, a device (see machine press) using a hydraulic cylinder to generate a compressive force
• Hydraulic pressure switch, a pressure switch with applications in automobiles
• Hydraulic ram, a cyclic water pump powered by hydropower
• Hydraulic rescue tools, used by emergency rescue personnel to assist vehicle extrication of crash victims, as well as other rescues from small spaces.
• Hydraulic seal, a relatively soft, non-metallic ring, captured in a groove or fixed in a combination of rings, forming a seal assembly, to block or separate fluid in reciprocating motion applications
• Hydraulic structure, a structure submerged or partially submerged in any body of water, which disrupts the natural flow of water
• Hydraulic tappet, a device for maintaining zero valve clearance in an internal combustion engine
• Hydraulic telegraph, either of two different hydraulic-telegraph telecommunication systems

Places

• Hydraulic, Virginia, an unincorporated community in Albemarle County, Virginia
• Hydraulic, a locality in the Cariboo Land District of British Columbia

Politics

• Hydraulic empire, a political structure which maintains power through exclusive control over access to water

Popular culture

• Hydraulic (Transformers), a fictional character, member of the Micromasters

Science

• Hydraulic analogy, the most widely used analogy for "electron fluid" in a metal conductor
• Hydraulic action, erosion that occurs when the motion of water against a rock surface produces mechanical weathering
• Hydraulic conductivity, a property of vascular plants, soils and rocks, that describes the ease with which a fluid (usually water) can move through pore spaces or fractures
• Hydraulic lift, a type of hydraulic machinery or a form of hydraulic redistribution, a plant root phenomenon
• Hydraulic redistribution, a plant root phenomenon
• Hydraulic retention time, a measure of the average length of time that a compound (ex. water) remains in a storage unit (ex. lake, pond, ocean)

Vehicles

• Hydraulic hybrid, a vehicle that uses a pressurized fluid power source, along with a conventional internal combustion engine
• USS Hydraulic (SP-2584), a United States Navy patrol vessel

Biology

• Hydraulic model of aggression, described by Konrad Lorenz in his 1963 book On Aggression