[buh-ril-ee-uh m]

noun Chemistry.

a steel-gray, bivalent, hard, light, metallic element, the salts of which are sweet: used chiefly in copper alloys for better fatigue endurance, in springs, and in electrical contacts. Symbol: Be; atomic weight: 9.0122; atomic number: 4; specific gravity: 1.8 at 20° C.

Origin of beryllium

1860–65; < Latin bēryll(us) beryl + -ium Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for beryllium

Historical Examples of beryllium

  • It is the machine that is not of iron and beryllium and crystal, but of pure, living force.

    The Last Evolution

    John Wood Campbell

  • Random samplings from various parts of the area show that the ash consists of magnesium, lithium, and beryllium carbonates.

    Anything You Can Do ...

    Gordon Randall Garrett

  • That was beryllium steel, the alloy from which the barriers at the terminals of the surta mine were fashioned.

  • Beryllium is estimated quantitatively by precipitation with ammonia, and ignition to oxide.

  • The mantel sank to ground level and the stereo swung outward, bringing into view a shining cubical locker of beryllium steel.


    Robert Donald Locke

British Dictionary definitions for beryllium



a corrosion-resistant toxic silvery-white metallic element that occurs chiefly in beryl and is used mainly in X-ray windows and in the manufacture of alloys. Symbol: Be; atomic no: 4; atomic wt: 9.012; valency: 2; relative density: 1.848; melting pt: 1289°C; boiling pt: 2472°CFormer names: glucinum, glucinium

Word Origin for beryllium

C19: from Latin bēryllus, from Greek bērullos
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for beryllium

metallic element, 1863, so called because it figures in the composition of the pale green precious stone beryl and was identified in emerald (green beryl) in 1797 by French chemist Louis Nicolas Vauquelin (1763-1829) and first isolated in 1828. At first and through 19c. also sometimes called glucinum or glucinium.

Online Etymology Dictionary, © 2010 Douglas Harper

beryllium in Medicine



n. Symbol Be

A lightweight, corrosion-resistant, toxic and possibly carcinogenic metallic element used in making precision instruments. Atomic number 4.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

beryllium in Science




A hard, lightweight, steel-gray metallic element of the alkaline-earth group, found in various minerals, especially beryl. It has a high melting point and is corrosion-resistant. Beryllium is used to make sturdy, lightweight alloys and aerospace structural materials. It is also used as a neutron moderator in nuclear reactors. Atomic number 4; atomic weight 9.0122; melting point 1,278°C; boiling point 2,970°C; specific gravity 1.848; valence 2. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.