irid·​i·​um i-ˈri-dē-əm How to pronounce iridium (audio)
: 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 PGMs are critical to the energy transition and demand for platinum and iridium are forecast to rise sharply, as both are used to make electrolyzers, a critical technology for producing low-emission hydrogen. Yusuf Khan, WSJ, 15 Nov. 2023 Triplet sensitizers typically contain a heavy metal like palladium, iridium, or platinum. Tracy H. Schloemer, IEEE Spectrum, 19 Sep. 2023 Platinum is part of the six platinum-group metals (PGM), including palladium, iridium, rhodium, ruthenium, and osmium. Laxmi Corp, The Salt Lake Tribune, 11 Sep. 2023 Supplies of copper, lithium, cobalt, iridium, and tin also may be crimped., 5 July 2023 The last fragments to survive will be its plutonium power supplies, still wrapped in the iridium and shielding meant to reduce risk to Earth during its launch nearly two decades ago. Mika McKinnon, Discover Magazine, 14 Sep. 2017 Across the globe, a thin layer of iridium — a chemical element that’s rare on Earth but common in extraterrestrial objects — entombs the dinosaurs like a coffin lid. Cody Cottier, Discover Magazine, 7 Apr. 2021 Dunn and Currano spent a month in the field looking for rocks bearing the telltale stripe of iridium deposits the asteroid strike left on Earth. Corinne Purtill, Los Angeles Times, 31 May 2023 Researchers determined the samples to be 99.5 percent carbon with inclusions of other trace elements such as troilite and iridium. Breanna Draxler, Discover Magazine, 1 July 2013

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'iridium.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History


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." See also osmium.

First Known Use

1804, in the meaning defined above

Time Traveler
The first known use of iridium was in 1804

Dictionary Entries Near iridium

Cite this Entry

“Iridium.” Dictionary, Merriam-Webster, Accessed 21 Apr. 2024.

Kids Definition


irid·​i·​um ir-ˈid-ē-əm How to pronounce iridium (audio)
: a rare silver-white hard brittle very heavy metallic element see element

Medical Definition


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

More from Merriam-Webster on iridium

Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!