triple point

American  

noun

Physics.

1. the particular temperature and pressure at which the solid, liquid, and gaseous phases of a given substance are all at equilibrium with one another.

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triple point British  

noun

1. chem the temperature and pressure at which the three phases of a substance are in equilibrium. The triple point of water, 273.16 K at a pressure of 611.2 Pa, is the basis of the definition of the kelvin

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triple point Scientific  

1. The temperature and pressure at which a substance can exist in equilibrium in the liquid, solid, and gaseous states. The triple point of pure water is at 0.01°C (273.16K, 32.01°F) and 4.58 mm (611.2Pa) of mercury and is used to calibrate thermometers.

2. Compare critical point

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triple point Cultural  

1. In physics, the temperature at which all three phases of matter (solid, liquid, and gas) for a given substance can coexist.

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Discover More

The triple point for water is a little above the freezing point, and is used to define temperature scales.

Etymology

Origin of triple point

First recorded in 1870–75

Example Sentences

Wind dynamics are usually stronger and foster a greater tornado risk near the triple point, but storms sometimes congeal and become messy.

From Washington Post

It’s at this time that you might have to make a tough call: Do you play the triple point, where warm/moist air, dry air and cold air all meet at the center of low pressure — or farther south along the cold front or dry line?

From Washington Post

The kelvin will soon be defined by the Boltzmann constant, which links energy and temperature, rather than in reference to conditions at a specific temperature of water, known as the triple point.

From Nature

The mole, meanwhile, is the amount of substance in a system with as many elementary entities as there are atoms in 0.012 kilograms of carbon-12, while the kelvin relates to the temperature and pressure at which water, ice and water vapour co-exist in equilibrium, known as the triple point of water.

From Nature

Voyager’s and Galileo’s observations suggest each thunderbolt emerges from deep in the atmosphere below Jupiter’s high ammonia clouds, in regions where temperatures and pressures reach the triple point of water and whirling maelstroms of vapor, rain and hail build up immense electric charges.

From Scientific American