mer·​cu·​ry | \ ˈmər-kyə-rē How to pronounce mercury (audio) , -k(ə-)rē \
plural mercuries

Definition of mercury

1a capitalized : a Roman god of commerce, eloquence, travel, cunning, and theft who serves as messenger to the other gods — compare hermes
b often capitalized, archaic : a bearer of messages or news or a conductor of travelers
2 [Middle English mercurie, from Medieval Latin mercurius, from Latin, the god]
a : a silver-white poisonous heavy metallic element that is liquid at ordinary temperatures and is used especially in batteries, in dental amalgam, and in scientific instruments

called also quicksilver

— see Chemical Elements Table
b : the column of mercury in a thermometer or barometer also : temperature the mercury rose above 70 degrees
3 capitalized : the planet nearest the sun — see Planets Table

Examples of mercury in a Sentence

In the summer, the mercury can reach over 100 degrees Fahrenheit.
Recent Examples on the Web Specifically, the group says the creek has shown signs of elevated concentrations of mercury, and elevated levels of arsenic, molybdenum, selenium, copper and thallium from mining in the area. William Thornton |, al, "New Alabama mammoth mine project long in the making," 1 Mar. 2020 McDonald claims that Seacole even harmed some troops by treating dysentery with lead and mercury. Tina Hillier, Smithsonian Magazine, "The Defiance of Florence Nightingale," 20 Feb. 2020 Tuna without the mercury and fish burgers without the fish. cleveland, "Beyond plant-based meat, General Mills is now investing in plant-based seafood," 16 Jan. 2020 The mercury soared well into the 90s from the nation’s capital to Florida to Texas, and just about everywhere in between., "It’s no different elsewhere up and down the Mid-Atlantic. Baltimore had reached 95 by noon, its hottest October day on record.," 3 Oct. 2019 The mercury soared to the mid-90s in Vienna on Wednesday and was expected to be in the 90s again on Thursday. NBC News, "Suspected gas line explosion in Vienna seriously injures at least two people," 26 June 2019 In Amarillo, the mercury soared into the 90s Thursday, near record levels, with wind gusts to 50 mph. Jason Samenow, Washington Post, "Wild storm charging across nation to unleash all modes of extreme weather through the weekend," 12 Apr. 2018 Opponents of vaccinations quote a number of scripture verses but, Hughes stressed, often use them to mask beliefs about GMOs or mercury content in vaccines. Cole Lauterbach, Washington Examiner, "Illinois lawmakers could remove religious exemption for child vaccination," 28 Feb. 2020 Once in the water, fish absorb mercury through their gills and their food. Ian Randall, Science | AAAS, "The real ‘paleo diet’ may have been full of toxic metals," 14 Feb. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'mercury.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of mercury

14th century, in the meaning defined at sense 1a

History and Etymology for mercury

Latin Mercurius, Roman god and the planet

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Time Traveler for mercury

Time Traveler

The first known use of mercury was in the 14th century

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Statistics for mercury

Last Updated

28 Mar 2020

Cite this Entry

“Mercury.” Dictionary, Merriam-Webster, Accessed 8 Apr. 2020.

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How to pronounce mercury (audio)

English Language Learners Definition of mercury

: a silver metal that is liquid at normal temperatures
: the mercury in a thermometer that shows the air's temperature
: the planet that is closest to the sun


mer·​cu·​ry | \ ˈmər-kyə-rē How to pronounce mercury (audio) \

Kids Definition of mercury

1 : a heavy silvery white poisonous metallic chemical element that is liquid at ordinary temperatures
2 : the column of mercury in a thermometer or barometer
3 capitalized : the planet that is nearest the sun and has a diameter of about 3000 miles (4700 kilometers)


mer·​cu·​ry | \ ˈmər-kyə-rē, -k(ə-)rē How to pronounce mercury (audio) \
plural mercuries

Medical Definition of mercury

1 : a heavy silver-white poisonous metallic element that is liquid at ordinary temperatures and used especially in scientific instruments symbol Hg

called also quicksilver

— see Chemical Elements Table
2 : a pharmaceutical preparation containing mercury or a compound of it

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More from Merriam-Webster on mercury

Spanish Central: Translation of mercury

Nglish: Translation of mercury for Spanish Speakers

Britannica English: Translation of mercury for Arabic Speakers Encyclopedia article about mercury

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