[ muh-lib-duh-nuh m ]
/ məˈlɪb də nəm /

noun Chemistry.

a silver-white metallic element, used as an alloy with iron in making hard, high-speed cutting tools. Symbol: Mo; atomic weight: 95.94; atomic number: 42; specific gravity: 10.2.

Nearby words

  1. molybdate,
  2. molybdate orange,
  3. molybdenite,
  4. molybdenosis,
  5. molybdenous,
  6. molybdenum disulfide,
  7. molybdenum trioxide,
  8. molybdic,
  9. molybdous,
  10. mom

Origin of molybdenum

1810–20; < New Latin, alteration of earlier molybdēna < Latin molybdaena < Greek molýbdaina galena, equivalent to mólybd(os) lead + -aina suffix of appurtenance Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for molybdenum

British Dictionary definitions for molybdenum


/ (mɒˈlɪbdɪnəm) /


a very hard ductile silvery-white metallic element occurring principally in molybdenite: used mainly in alloys, esp to harden and strengthen steels. Symbol: Mo; atomic no: 42; atomic wt: 95.94; valency: 2–6; relative density: 10.22; melting pt: 2623°C; boiling pt: 4639°C

Word Origin for molybdenum

C19: from New Latin, from Latin molybdaena galena, from Greek molubdaina, from molubdos lead

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 molybdenum



metallic element, 1816, from molybdena, used generally for lead-like minerals, from Greek molybdos "lead," also "black graphite," related to Latin plumbum "lead" (see plumb (n.)), and like it probably borrowed from a lost Mediterranean language, perhaps Iberian. The element so called because of its resemblance to lead ore.

Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for molybdenum


[ mə-lĭbdə-nəm ]

n. Symbol Mo

A hard metallic element that is an essential trace element in plant and animal nutrition. Atomic number 42.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

Science definitions for molybdenum


[ mə-lĭbdə-nəm ]


A hard, silvery-white metallic element that resists corrosion and retains its strength at high temperatures. It is used to harden and toughen steel and to make high-temperature wiring. Molybdenum is an essential trace element in plant metabolism. Atomic number 42; atomic weight 95.96; melting point 2,623°C; boiling point 4,639°C; specific gravity 10.22 (at 20°C); valence 2, 3, 4, 5, 6. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.