[ mur-kyuh-ree ]
/ ˈmɜr kyə ri /
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noun, plural mer·cu·ries.
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Origin of mercury

1300–50; Middle English Mercurie<Medieval Latin, Latin Mercurius, akin to merx goods
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use mercury in a sentence

British Dictionary definitions for mercury (1 of 3)

/ (ˈmɜːkjʊrɪ) /

noun plural -ries
Also called: quicksilver, hydrargyrum a heavy silvery-white toxic liquid metallic element occurring principally in cinnabar: used in thermometers, barometers, mercury-vapour lamps, and dental amalgams. Symbol: Hg; atomic no: 80; atomic wt: 200.59; valency: 1 or 2; relative density: 13.546; melting pt: –38.842°C; boiling pt: 357°C
any plant of the euphorbiaceous genus MercurialisSee dog's mercury
archaic a messenger or courier

Word Origin for mercury

C14: from Latin Mercurius messenger of Jupiter, god of commerce; related to merx merchandise

British Dictionary definitions for mercury (2 of 3)

/ (ˈmɜːkjʊrɪ) /

Roman myth the messenger of the godsGreek counterpart: Hermes

British Dictionary definitions for mercury (3 of 3)

/ (ˈmɜːkjʊrɪ) /

the second smallest planet and the nearest to the sun. Mean distance from sun: 57.9 million km; period of revolution around sun: 88 days; period of axial rotation: 59 days; diameter and mass: 38 and 5.4 per cent that of earth respectively
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Scientific definitions for mercury (1 of 2)

[ mûrkyə-rē ]

A silvery-white, dense, poisonous metallic element that is a liquid at room temperature and is used in thermometers, barometers, batteries, and pesticides. Atomic number 80; atomic weight 200.59; melting point -38.87°C; boiling point 356.58°C; specific gravity 13.546 (at 20°C); valence 1, 2. See Periodic Table.

Word History

Like a few other elements, mercury has a chemical symbol, Hg, that bears no resemblance to its name. This is because Hg is an abbreviation of the Latin name of the element, which was hydrargium. This word in turn was taken over from Greek, where it literally meant “water-silver.” With this name the Greeks were referring to the fact that mercury is a silvery liquid at room temperature, rather than a solid like other metals. Similarly, an older English name for this element is quicksilver, which means “living silver,” referring to its ability to move like a living thing. (The word quick used to mean “alive,” as in the Biblical phrase “the quick and the dead.”) The name mercury refers to the fact that the element flows about quickly: the name comes from the Roman god Mercury, who was the swift-footed messenger of the gods.

Scientific definitions for mercury (2 of 2)


The planet closest to the Sun and the smallest in the solar system. Mercury is a terrestrial or inner planet, second in density only to Earth, with a rugged, heavily-cratered surface similar in appearance to Earth's Moon. Its rotational period of 58.6 days is two-thirds of its 88-day orbital period, thus, it makes three full axial rotations every two years. Mercury's atmosphere is almost nonexistent; this fact, which produces rapid radiational cooling on its dark side, together with its proximity to the Sun, gives it a temperature range greater than any other planet in the solar system, from 466° to -184°C (870° to -300°F). Because it is so close to the Sun, Mercury is only visible shortly before sunrise or after sunset, and observation is further hindered by the fact that its light must pass obliquely through the lower atmosphere where it is distorted or filtered by dust and pollution. See Table at solar system.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

Cultural definitions for mercury (1 of 3)


In chemistry, a heavy, silvery metallic element, a liquid at normal temperatures. Mercury expands or contracts rapidly in response to changes in temperature and therefore was once widely used in thermometers.

notes for mercury

The term mercury is used figuratively in such expressions as “The mercury's rising” to mean that the temperature is going up.

Cultural definitions for mercury (2 of 3)


The Roman name of Hermes, the messenger of the Greek and Roman gods.

notes for Mercury

The planet nearest the sun is named Mercury. It moves swiftly in its orbit like the messenger of the gods.

Cultural definitions for mercury (3 of 3)


In astronomy, the planet closest to the sun, named after the fleet-footed messenger of the Roman gods (see under “Mythology and Folklore”) because of its swift movement in its orbit. Mercury takes only eighty-eight days to go around the sun. (See solar system.)

notes for Mercury

Mercury is sometimes visible from the Earth as a morning or evening star.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.