absolute zero

the temperature of −273.16°C (−459.69°F), the hypothetical point at which all molecular activity ceases.
Dictionary.com Unabridged

absolute temperature scale

noun Thermodynamics.
temperature (absolute temperature) as measured on a scale in which the hypothetical lowest limit of physical temperatures is assigned the value zero (absolute zero) as the Kelvin scale.
Also called absolute scale.
Dictionary.com Unabridged
Cite This Source Link To absolute zero
World English Dictionary
absolute zero
the lowest temperature theoretically attainable, at which the particles constituting matter would be in the lowest energy states available; the zero of thermodynamic temperature; zero on the International Practical Scale of Temperature: equivalent to --273.15°C or --459.67°F

Collins English Dictionary - Complete & Unabridged 10th Edition
Cite This Source
Word Origin & History

absolute zero
the idea dates back to 1702 and its general value was guessed to within a few degrees soon thereafter, but not precisely discovered until Lord Kelvin's work in 1848. It was known by many names, e.g. infinite cold, absolute cold, natural zero of temperature; the term absolute zero was among them by 1806.
Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source
American Heritage
Medical Dictionary

absolute zero n.
The temperature at which substances possess no thermal energy, equal to -273.15°C, -459.67°F, or 0 K.

The American Heritage® Stedman's Medical Dictionary
Cite This Source
American Heritage
Science Dictionary
absolute temperature scale  
A temperature scale having absolute zero as the lowest temperature. Absolute temperature scales only have positive numbers. The Kelvin scale and the Rankine scale are absolute temperature scales. Compare relative temperature scale.
absolute zero  
The lowest possible temperature, at which all molecules are have the least possible amount of kinetic energy. Absolute zero is equal to 0°K, -459.67°F, or -273.15°C. At temperatures approaching absolute zero, the physical characteristics of some substances change significantly. For example, some substances change from electrical insulators to conductors, while others change from conductors to insulators. Absolute zero has never been reached in laboratory experiments. See also Bose-Einstein condensate, zero-point energy.

Our Living Language  : The temperature of a substance is determined by the average velocity of its molecules: the faster they move, the warmer the substance. At absolute zero molecules have minimal kinetic energy (or zero-point energy) and heat energy cannot be extracted from them. The molecules are not motionless, however, due to the uncertainty principle of quantum mechanics, which entails that the atoms cannot have both a fixed position and zero momentum at the same time; instead, the molecules of a substance at absolute zero are always "wiggling" in some manner. Absolute zero is zero degrees Kelvin, equal to -273.15 degrees Celsius and -459.67 degrees Fahrenheit. The coldest known place in the universe is the Boomerang Nebula, where the temperature is -272° Celsius. Scientists at Massachusetts Institute of Technology have gone much lower than that by using laser traps and other techniques to cool rubidium to 2 × 10-9 degrees Kelvin.

The American Heritage® Science Dictionary
Cite This Source
American Heritage
Cultural Dictionary

absolute zero definition

The lowest temperature that can be attained by matter, corresponding to the point at which most motion in atoms stops. Absolute zero is about –273 degrees on the Celsius scale and about –460 on the Fahrenheit scale.

The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
Cite This Source
Example sentences
Unfortunately, the standard definition of a second relies on what the atom does
  at a temperature of absolute zero.
For example, the isotopes of fluid helium are mixing spontaneously even at the
  absolute zero temperature.
The oscillations increased in frequency when the temperature was reduced to
  less than two-tenths of a degree above absolute zero.
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature