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Hydrophilic

Attraction to water.

Hydroplane

The action of a tire rolling on a layer of water on the road surface instead of staying in contact with the pavement. Hydroplaning occurs when water cannot be displaced from between the tread and the road.

Hydrostatic Pressure

The pressure exerted by a fluid.

Hygroscopic

Readily absorbing and retaining moisture.

Hyperlink

An element in an electronic document that links to another place in the document or to an entirely different document.

Hypertext

A special type of a database system, in which objects ( text, pictures, music, programs, and so on ) can be creatively linked to each other.

Hypoid Gear

The combination of a ring gear and a pinion gear in which the pinion meshes with the ring gear below the centerline of the ring gear. Commonly used in automotive final drives and starter motors.

Hysteresis Bands

The area between two curves on a graph that indicates when a torque converter locks and unlocks. Hysteresis bands exist between graph curves that indicate when a transmission will upshift or downshift.

Hz

Hertz.