• a solid silvery grey radioactive transuranic element whose atoms can be split when bombarded with neutrons; found in minute quantities in uranium ores but is usually synthesized in nuclear reactors; 13 isotopes are known with the most important being plutonium 239
Example sentence
• The United States has stockpiled tons of plutonium.
• a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons
Example sentence
• The name hafnium derives from Hafnia, the Latin name for Copenhagen.
• a toxic nonmetallic element related to sulfur and tellurium; occurs in several allotropic forms; a stable grey metallike allotrope conducts electricity better in the light than in the dark and is used in photocells; occurs in sulfide ores (as pyrite)
Example sentence
• The nutritional intake of selenium is important for human health.
• a lustrous grey strong metallic element resembling titanium; it is used in nuclear reactors as a neutron absorber; it occurs in baddeleyite but is obtained chiefly from zircon
Example sentence
• The zirconium oxide coating on the surface of certain metals provides excellent protection against corrosion.
• a white metallic element that burns with a brilliant light; the fifth most abundant element in the earth's crust; an important component of most plants and animals
Example sentence
• Milk and dairy products are excellent sources of calcium.
Note: This list has been curated by our developer and author and fine-tuned since 2016 with manual additions, exclusions and rankings. Thousands of user contributions from rappers, singers, songwriters and poets have also been used for accuracy.
