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 But in general, the bigger the predator, the more mercury that is likely accumulated., "Florida hunter makes Christmas cookies with python eggs," 28 Dec. 2020 The duo has introduced legislation that would create a national program to monitor mercury pollution in the air and water, authorizing $95 million over three years. Josh Siegel, Washington Examiner, "Daily on Energy, presented by API: Congressional leaders in talks for last-minute deal on long-sought energy innovation package," 8 Dec. 2020 Burning coal releases mercury into the atmosphere and rain brings it back down to the ground, making its way into the food chain and into fish, Bruner said. Bob Pepalis, Washington Examiner, "Impaired waters report by Iowa department identifies potential trouble spots to fix," 29 Dec. 2020 The body eliminates it more easily than the second type, called methyl mercury, which is found in contaminated fish. Anne P. Kim, The Conversation, "Ingredients in flu vaccine won’t hurt you – two pharmacists explain why," 13 Nov. 2020 And the LEDs contain no mercury, and power on immediately without any warmup time. Rachel King, Fortune, "Must-have gadgets and accessories for safer winter (and pandemic) travel," 6 Nov. 2020 As Inspector Katz spoke, tension in the room rose like the mercury in a rectal thermometer. Washington Post, "Style Invitational Week 1415: The Year in Redo, Part 1," 17 Dec. 2020 High levels of mercury and other chemicals were found in the blood of firefighters after the Tubbs Fire. Mallory Moench,, "‘No end in sight’: California firefighters battle exhaustion, heat and pandemic in historic wildfire season," 16 Sep. 2020 The Conservation Federation sued, arguing that the project would release mercury and lead, among other dangerous pollutants, according to articles from the Minneapolis Star, the Minneapolis Tribune and the Associated Press. Greg Stanley, Star Tribune, "Duluth Harbor dredging, beach restoration work might violate old pact," 1 Sep. 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

18 Jan 2021

Cite this Entry

“Mercury.” Dictionary, Merriam-Webster, Accessed 22 Jan. 2021.

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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

Nglish: Translation of mercury for Spanish Speakers

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

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