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

Unsurprisingly, the cod ended up with lower mercury levels than the dogfish. Linda Carroll, NBC News, "Climate change and overfishing could lead to higher mercury levels in fish," 7 Aug. 2019 The average high temperature will fall every day from now until Dec. 12, when the mercury bottoms out at 42 degrees. Chris Bianchi, The Denver Post, "Winter is coming: Starting today, Denver’s average high drops until December," 2 Aug. 2019 Meteorologists predict temperatures in the UK could reach 102.2 degrees Fahrenheit, while France could see the mercury rise to a shocking 107.6 in Paris. Aj Willingham, CNN, "5 things to know for July 25: Mueller, North Korea, Europe heat wave," 25 July 2019 And as the mercury rises, so do people’s reliance on fossil fuels, creating even more pollution. Benjamin Storrow, Scientific American, "As Temperatures Soar During Heat Wave, So Will CO2," 19 July 2019 Those populations may want to limit their intake of mercury due to impacts on developing nervous systems. Dennis Pillion |,, "What not to eat: Alabama’s 2019 fish consumption advisories," 17 July 2019 Port Authority officials have said the sloping topography and mercury contamination in the soil have proven more difficult to address than the private market cares to handle on its own. Frederick Melo, Twin Cities, "St. Paul Port Authority plans vote on buying Hillcrest golf course for $10M," 11 June 2019 But here’s the key: get cool air into your home at night by opening up your winows after the sun goes down and the mercury drops. Emily Sweeney,, "Heat hacks: 12 tips and tricks to keeping your house cool," 19 July 2019 During the city’s long, excruciatingly hot summers, the mercury can drop by as much as 20 blissful degrees at sundown. Patricia Escárcega,, "Exploring Hermosillo, northern Mexico’s great unsung food city," 26 June 2019

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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Statistics for mercury

Last Updated

16 Aug 2019

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Time Traveler for mercury

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

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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

Comments on mercury

What made you want to look up mercury? Please tell us where you read or heard it (including the quote, if possible).


a period when something is suspended

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