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

On the audio side, the One relies on 40-mm beryllium drivers, active noise cancellation, and an ambient mode backed by six microphones. — New Atlas, 8 Oct. 2026

Long-term exposure to arsenic, beryllium, cadmium, chromium, nickel and diesel exhaust has also been linked to lung cancer. — Emily Cegielski, Flow Space, 31 July 2026

It will reportedly be located at NGK’s existing beryllium facility. — Georgina Jedikovska, Interesting Engineering, 16 July 2026

The probe was made of mostly titanium, with beryllium shelves and aluminum equipment boxes inside. — Emma Gometz, Scientific American, 10 May 2026

Word History

Etymology

New Latin, from Greek bēryllion

First Known Use

circa 1847, in the meaning defined above

Rhymes for beryllium

• ileum
• lilium
• psyllium
• trillium
• concilium
• penicillium
• verticillium

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