thermometer

noun

ther·​mom·​e·​ter thər-ˈmä-mə-tər How to pronounce thermometer (audio)
thə-ˈmä-mə-tər
plural thermometers
: an instrument for determining temperature
specifically : one consisting of a sensor housed in a metal probe that registers a change in electrical resistance as a change in temperature

Examples of thermometer in a Sentence

Recent Examples on the Web
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Grill the potatoes, cut sides down first, then flip with tongs, until golden brown, crispy on the edges, and easily punctured by a thermometer probe. — Candy Hom, AJC.com, 10 Oct. 2026 Heat, whisking constantly, until sugar is dissolved and an instant-read thermometer registers 170°. — Tanya Bush, Bon Appetit Magazine, 10 Oct. 2026 There are many ways to make the candy, but this method doesn’t require a thermometer or timer. — Jack Dolan, Los Angeles Times, 6 Oct. 2026 The combination was as oppressive as the thermometer reading. — Fabian Ardaya, New York Times, 4 Oct. 2026 See All Example Sentences for thermometer

Word History

Etymology

French thermomètre, from Greek thermē heat + French -o- + -mètre -meter — more at therm

First Known Use

1633, in the meaning defined above

Time Traveler
The first known use of thermometer was in 1633

Cite this Entry

“Thermometer.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/thermometer. Accessed 16 Oct. 2026.

Kids Definition

thermometer

noun
: an instrument for measuring temperature

Medical Definition

thermometer

noun
: an instrument for determining temperature that usually consists either of a device providing a digital readout or of a glass bulb attached to a fine tube of glass with a numbered scale and containing a liquid (as mercury or colored alcohol) that is sealed in and rises and falls with changes of temperature

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