Hot spots in subatomic physics are regions of high energy density or temperature in hadronic or nuclear matter.

A hot spring is a spring produced by the emergence of geothermally heated groundwater that rises from the Earth's crust.

A hot stick is an insulated pole, usually made of fiberglass, used by electric utility workers when engaged on live-line working on energized high-voltage electric power lines, to protect them from electric shock.

Hot Wet Rock (HWR) hydrothermal technology makes use of hot fluids found naturally in basement rock.

Work involving sources of ignition or temperature sufficiently high to cause the ignition of a flammable gas mixture.

Hot working process metals are plastically deformed above their recrystallization temperature.

A vessel riding on a cushion of air formed under it. It is very manoeuvrable and is also amphibious. There are two types of hovercrafts: the fully skirted and the sidewall.

A speed trial evaluation method developed by the Hamburg Ship Model Basin (HSVA) in order to improve the significance of full-scale measurements.

The rotating component of the wind turbine to which the rotor blades are fixed.

Hub height is the height of the rotor axis above the ground.

The structural body of a ship, including shell plating, framing, decks, bulkheads, etc.

Any protruding part of the hull structure that is below the waterline (rudder, bilge keels, thrusters, propeller brackets etc).

The ratio of thrust power to effective power, which is usually higher than one.

Hull roughness is the result of fouling, corrosion, flaking of old paint, mechanical damages during service, etc.

A system of measuring stresses in selected locations of a hull girder. The system usually includes a database in which measurements are recorded for subsequent reference.

Environmental changes caused directly or indirectly by humans.

A humid continental climate is a climatic region typified by four distinct seasons and large seasonal temperature differences, with warm to hot (and often humid) summers and cold (sometimes severely cold in the northern areas) winters.

A humid subtropical climate is a zone of climate characterized by hot and humid summers, and cold to mild winters.

The concentration of water vapor present in the air.

A criterion used in the design of offshore oilrigs and meant to represent most severe conditions that may occur once in a hundred years.