beryllium

noun

be·​ryl·​li·​um bə-ˈri-lē-əm 

: 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

And metal, specifically beryllium, is the material for the walls of ITER. —Jacek Krywko, Ars Technica, 3 May 2024

These use either fluoride or chloride salts, often mixed with lithium or beryllium. —Allison MacFarlane, Foreign Affairs, 8 July 2021

Turning the rods with the beryllium side in sustains the fission reaction. —Amy Shira Teitel, Discover Magazine, 28 Mar. 2019

The early universe was made of something like 75% hydrogen, 25% helium, and traces of lithium and beryllium (that is, elements one through four, for those of you looking at a table of the elements). —Korey Haynes, Discover Magazine, 22 Oct. 2018

Word History

Etymology

New Latin, from Greek bēryllion

First Known Use

circa 1847, in the meaning defined above

Kids Definition

beryllium

noun

be·​ryl·​li·​um bə-ˈril-ē-əm 

: a steel-gray light strong brittle toxic metallic element used chiefly to help harden alloys see element

Medical Definition

beryllium

noun

be·​ryl·​li·​um bə-ˈril-ē-əm 

: a steel-gray light strong brittle toxic bivalent metallic element used chiefly as a hardening agent in alloys

—symbol Be see Chemical Elements Table