be·​ryl·​li·​um | \ bə-ˈri-lē-əm How to pronounce beryllium (audio) \

Definition of beryllium

: a chemical element of the alkaline earth metal group with atomic number 4 that occurs naturally in minerals such as beryl and is steel-gray in color, light and strong but brittle, and is used chiefly as a hardening agent in alloys — see Chemical Elements Table

Examples of beryllium in a Sentence

Recent Examples on the Web The earphones feature a detachable high-spec cable with beryllium and Copper MMCX connectors. Mark Sparrow, Forbes, 4 May 2022 These contain toxins such as mercury, lead, beryllium, and arsenic, which can be harmful to the environment and our health. Miriam Porter, House Beautiful, 22 Apr. 2022 The inner vessel wall of the tokamak was upgraded from graphite to beryllium. David Donovan, The Conversation, 4 Apr. 2022 To counter this, JET now has a special tungsten and beryllium shielding that will also be part of ITER. Caroline Delbert, Popular Mechanics, 16 Feb. 2022 Partly so that the telescope would not be too heavy to launch, engineers chose to make the mirrors out of the relatively lightweight element beryllium. Richard Panek, Scientific American, 25 Dec. 2021 Webb’s main mirror is made of beryllium, a lightweight yet sturdy and cold-resistant metal. Marcia Dunn, Anchorage Daily News, 9 Jan. 2022 My main mirror is 21 ft (6.4 m) across and is made of 18 hexagonal segments of beryllium, which is really good at keeping its shape in cold temperatures. Nicolás Rivero, Quartz, 27 Dec. 2021 Engineers built that mirror out of beryllium, a relatively rare metal that’s lighter than aluminum but stronger than steel. Nadia Drake, Science, 25 Dec. 2021 See More

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'beryllium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of beryllium

circa 1847, in the meaning defined above

History and Etymology for beryllium

New Latin, from Greek bēryllion

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Time Traveler for beryllium

Time Traveler

The first known use of beryllium was circa 1847

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Dictionary Entries Near beryllium



beryllium oxide

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Last Updated

15 May 2022

Cite this Entry

“Beryllium.” Dictionary, Merriam-Webster, Accessed 18 May. 2022.

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More Definitions for beryllium


be·​ryl·​li·​um | \ bə-ˈril-ē-əm How to pronounce beryllium (audio) \

Medical Definition of beryllium

: a steel-gray light strong brittle toxic bivalent metallic element used chiefly as a hardening agent in alloys symbol Be — see Chemical Elements Table

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