mercury

noun

mer·​cu·​ry ˈmər-kyə-rē 

-k(ə-)rē

plural mercuries

1

a

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

Now harmful chemicals, which may include asbestos, lead, mercury and other heavy metals, are present in the ash that blankets the burn zones. —Ryan Fonseca, Los Angeles Times, 29 Jan. 2025

In 1260, Vincent of Beauvais gave instructions to travelers to use poultices (a dressing for wounds) made of oil, plants and quicksilver (mercury) to prevent and manage blisters — an all too frequent ailment experienced by pilgrims walking long distances. —Megan Cassidy-Welch, CNN, 24 Jan. 2025

Forecasters said temperatures during the noon event could fall to around 22 degrees, the chilliest since Ronald Reagan's second inauguration in January of 1985, when the mercury plummeted to 7 degrees. —Megan Cerullo, CBS News, 17 Jan. 2025

Silver Amalgam Fillings Silver amalgam fillings consist of a combination of metals that include silver, mercury, tin, and copper. —Anna Giorgi, Verywell Health, 10 Jan. 2025

Word History

Etymology

Latin Mercurius, Roman god and the planet

First Known Use

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

Phrases Containing mercury

• bichloride of mercury
• mercury chloride
• mercury-vapor lamp

Kids Definition

mercury

noun

mer·​cu·​ry ˈmər-kyə-rē 

-k(ə-)rē

1

a

: a heavy silver-white poisonous metallic element that is liquid at ordinary temperatures

called also quicksilver

see element

b

: the column of mercury in a formerly common type of thermometer or barometer

2

capitalized : the planet nearest the sun see planet

Medical Definition

mercury

noun

mer·​cu·​ry ˈmər-kyə-rē, -k(ə-)rē 

plural mercuries

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