dry-bulb thermometer

noun

variants or dry bulb thermometer
plural dry-bulb thermometers or dry bulb thermometers
: a thermometer that uses a bulb filled with liquid (such as mercury or alcohol) to register a reading of the temperature of the atmosphere based on the known expansion rate of the liquid : a thermometer that measures dry-bulb temperature
The dry-bulb thermometer, as the name would imply is an ordinary mercury thermometer the bulb of which is maintained in a dry state.T. Morris Fraser
A wet piece of cloth covers the bulb of one, the wet-bulb thermometer, which is cooled by evaporation of water in the cloth. The other thermometer, a dry-bulb thermometer, measures the air temperature. The difference between the two thermometers' readings is used in a mathematical formula to determine the dew point and relative humidity.The New York Times

Examples of dry-bulb thermometer in a Sentence

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The difference between these two thermometer measurements is charted against the actual air temperature (the temperature shown on the dry-bulb thermometer) to determine relative humidity (see also hygrometer). John P. Rafferty, Encyclopedia Britannica, 7 Apr. 2026

Word History

First Known Use

1830, in the meaning defined above

Time Traveler
The first known use of dry-bulb thermometer was in 1830

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Cite this Entry

“Dry-bulb thermometer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/dry-bulb%20thermometer. Accessed 20 Apr. 2026.

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