na·​cre·​ous ˈnā-krē-əs How to pronounce nacreous (audio) -k(ə-)rəs How to pronounce nacreous (audio)
: possessing the qualities of, consisting of, or abounding in nacre
also : iridescent

Examples of nacreous in a Sentence

the nacreous lining of the shell of a mollusk
Recent Examples on the Web Tiffany has a long-standing history with pearls, both nacreous—from oysters and mollusks—and non-nacreous, like Melo Melo pearls. Stellene Volandes, Town & Country, 20 Feb. 2021 Unfortunately, nacreous clouds also support chemical reactions that convert benign chlorine-containing molecules into a form that destroys Earth’s ozone layer. Rebecca Coffey, Discover Magazine, 29 Jan. 2012 Quahogs produce non-nacreous, porcelainlike pearls, according to the Gemological Institute of America. Shannon Marvel McNaught, USA TODAY, 16 Aug. 2022 Markov processes include an element of randomness—in this case, the thickness of the outermost nacreous layer—but one that can be influenced by the system’s history. Leila Sloman, Popular Mechanics, 28 Feb. 2022 An alternative explanation is that the red skies were the result of nacreous clouds common to that particular latitude. Jennifer Ouellette, Ars Technica, 21 May 2020 Also called polar stratospheric clouds (or less precisely, rainbow clouds), nacreous clouds normally only form in high latitudes and at extremely cold temperatures. National Geographic, 3 Feb. 2016 The cold air the storm blew in also led to the formation of beautiful nacreous clouds. National Geographic, 3 Feb. 2016 See More

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

Word History

First Known Use

1819, in the meaning defined above

Time Traveler
The first known use of nacreous was in 1819

Dictionary Entries Near nacreous

Cite this Entry

“Nacreous.” Dictionary, Merriam-Webster, Accessed 9 Dec. 2023.

Medical Definition


na·​cre·​ous ˈnā-krē-əs How to pronounce nacreous (audio) -k(ə-)rəs How to pronounce nacreous (audio)
: having a pearly appearance
nacreous bacterial colonies

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