Definition of "beryllium" [be•ryl•li•um]

• A high-melting, lightweight, corrosion-resistant, rigid, steel-gray metallic element used as an aerospace structural material, as a moderator and reflector in nuclear reactors, and in a copper alloy used for springs, electrical contacts, and nonsparking tools. Atomic number 4; atomic weight 9.0122; melting point 1,278°C; boiling point 2,970°C; specific gravity 1.848; valence 2. See Table at element. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Long-term beryllium exposure can increase the risk of developing lung cancer."
• "Around the plutomum is a cylinder of beryllium, which is a godsend for our purposes."
• "'Now, around the beryllium is a cylinder of tungsten-rhenium, which we need for its density We will purchase twelve kilograms in powder form, which we will sinter into cylindrical segments."