irid·​i·​um | \ i-ˈri-dē-əm How to pronounce iridium (audio) \

Definition of iridium

: a rare silver-white hard brittle very heavy metallic element — see Chemical Elements Table

Examples of iridium in a Sentence

Recent Examples on the Web

To increase their stability, the prototypes were reforged in 1889 out of a platinum-iridium alloy and stowed under lock and key. Robert Rathe, National Geographic, "The kilogram is forever changed. Here's why that matters.," 20 May 2019 Geologists soon found a similar iridium layer at the same geological strata in other parts of the world. Nina Burleigh, Newsweek, "We Can Save Ourselves From Earth-Killing Asteroids, But Someone Has to Pay," 11 June 2015 Iron meteorites: Typically consist of approximately 90 to 95% iron, with the remainder comprised of nickel and trace amounts of heavy metals, including iridium, gallium and sometimes gold. Perry A. Farrell, Detroit Free Press, "Which type of meteorite landed in Michigan? NASA 90% sure it knows," 17 Jan. 2018 In 2011, researchers led by Richard Masel, a chemist and CEO of Dioxide Materials in Boca Raton, Florida, tested a setup with silver and iridium oxide catalysts and a liquid electrolyte to promote the CO2 to CO reaction. Robert Service, Science | AAAS, "Two new ways to turn ‘garbage’ carbon dioxide into fuel," 1 Sep. 2017 When the Earth was forming, most iridium sank below the molten crust. Michael Ordoña, San Francisco Chronicle, "Nye documentary born in S.F.," 2 Nov. 2017 Project officials said once the iridium melts, the plutonium will be dispersed into the atmosphere. Washington Post, "NASA’s Saturn-orbiting Cassini spacecraft faces fiery finish," 12 Sep. 2017 Ni says the company is looking for cheaper options to replace iridium, a rare and expensive metal. Robert Service, Science | AAAS, "Two new ways to turn ‘garbage’ carbon dioxide into fuel," 1 Sep. 2017 There is reason to believe that some asteroids are rich in valuable metals, such as platinum and iridium. The Economist, "Space travelA new way of propelling spacecraft may open up the asteroid belt," 21 Sep. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'iridium.' 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 iridium

1804, in the meaning defined above

History and Etymology for iridium

Greek īrid-, îris "rainbow, iridescent halo around the moon, a flame, etc., iris entry 1" + New Latin -ium -ium; from the colors produced by dissolving it in hydrochloric acid

Note: The word iridium was introduced by the English chemist Smithson Tennant (1761-1815) in Philosophical Transactions of the Royal Society, 1804, Part II, p. 414: "As it is necessary to give some name to bodies which have not been known before, and most convenient to indicate by it some characteristic property, I should incline to call this metal Iridium, from the striking variety of colours which it gives, while dissolving in marine acid."

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Last Updated

20 Jun 2019

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Time Traveler for iridium

The first known use of iridium was in 1804

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More Definitions for iridium


irid·​i·​um | \ i-ˈri-dē-əm How to pronounce iridium (audio) \

Kids Definition of iridium

: a hard brittle heavy metallic chemical element


irid·​i·​um | \ ir-ˈid-ē-əm How to pronounce iridium (audio) \

Medical Definition of iridium

: a silver-white hard brittle very heavy metallic element of the platinum group used especially in hardening platinum for alloys (as for surgical instruments) symbol Ir — see Chemical Elements Table

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Spanish Central: Translation of iridium

Nglish: Translation of iridium for Spanish Speakers Encyclopedia article about iridium

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appealing forcibly to the mind or reason

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