mer·​cu·​ry | \ˈmər-kyə-rē, -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

As the mercury rises, Chicago residents can call 311 to request well-being checks for elderly friends or family members, or for information on the closest cooling center. Morgan Greene,, "Excessive heat watch upgraded to warning: 'dangerously hot temperatures' in Chicago area," 29 June 2018 But in Turkey’s simultaneously controlled and precarious climate, eleven-a-side dramas can be both tool and indicator: to take the country’s political temperature, read the mercury in its soccer. Patrick Keddie, The New Republic, "Understanding Authoritarianism Through Soccer," 7 May 2018 The waste byproduct contains toxic metals like lead, mercury and arsenic. Washington Post, "North Carolina consumers could see $5B coal-ash cleanup bill," 6 July 2018 Though often laced with lead, mercury or other toxic substances, laptops and phones also contain valuable elements like gold, silver and copper. New York Times, "E-Waste Offers an Economic Opportunity as Well as Toxicity," 5 July 2018 Electronics contain heavy metals, including lead, mercury, cadmium, and hexavalent chromium that can be harmful if released into the environment. Amy Lavalley, Post-Tribune, "Electronics drop-off locations reduced by one in Porter County," 1 May 2018 The facilities in question emit hazardous air pollutants that include hydrochloric acid, lead, mercury, ethylbenzene, benzene and formaldehyde. Alex Stuckey, Houston Chronicle, "Air pollution in Houston/Galveston region could increase under EPA-created loophole, study finds," 10 Apr. 2018 According to the release, coal dust contains toxic metals such as lead, mercury, and arsenic. Erik S. Hanley, Milwaukee Journal Sentinel, "Black dust found on Oak Creek homes confirmed to be coal by independent study," 13 Mar. 2018 Recommendations for fish can be confusing and many people are scared to eat fish because of safety concerns related to mercury and other toxins. Bianca Arney,, "Eating fish for your best health," 2 May 2018

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

8 Nov 2018

Look-up Popularity

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

Mercury : the planet that is closest to the sun


mer·​cu·​ry | \ˈmər-kyə-rē \

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 \
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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to clear from alleged fault or guilt

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