• synonyms


[bawr-on, bohr-]
noun Chemistry.
  1. a nonmetallic element occurring naturally only in combination, as in borax or boric acid, and obtained in either an amorphous or a crystalline form when reduced from its compounds. Symbol: B; atomic weight: 10.811; atomic number: 5.
Show More

Origin of boron

1805–15; bor(ax1) + (carb)on
Related formsbo·ron·ic [boh-ron-ik, baw-, buh-] /boʊˈrɒn ɪk, bɔ-, bə-/, adjective
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for boron

Historical Examples

  • We tried silicon and boron, and a lot of things that I have forgotten now.

    Historic Inventions

    Rupert S. Holland

  • His results indicated that fruits are relatively rich in boron.

  • Tobacco is so rich in boron that it can be detected in the ash of one cigarette.

  • With an unstable fuel like boron hydride, that made the difference.

    The Scarlet Lake Mystery

    Harold Leland Goodwin

  • Recent developments indicate that the metal, boron, may play an important part in the metallurgy of various metals.

British Dictionary definitions for boron


  1. a very hard almost colourless crystalline metalloid element that in impure form exists as a brown amorphous powder. It occurs principally in borax and is used in hardening steel. The naturally occurring isotope boron-10 is used in nuclear control rods and neutron detection instruments. Symbol: B; atomic no: 5; atomic wt: 10.81; valency: 3; relative density: 2.34 (crystalline), 2.37 (amorphous); melting pt: 2092°C; boiling pt: 4002°C
Show More

Word Origin

C19: from bor (ax) + (carb) on
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 boron


1812, from borax + ending abstracted unetymologically from carbon (it resembles carbon). Originally called boracium by Humphrey Davy because it was drawn from boracic acid. Related: Boric.

Show More
Online Etymology Dictionary, © 2010 Douglas Harper

boron in Medicine


n. Symbol B
  1. A soft, nonmetallic element found in compounds that are used in treating cancer and as astringents and antiseptics. Atomic number 5.
Show More
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.

boron in Science


  1. A shiny, brittle, black metalloid element extracted chiefly from borax. It is a good electrical conductor at high temperatures and a poor conductor at low temperatures. Boron is necessary for the growth of land plants and is used in the preparation of soaps, abrasives, and hard alloys. It is also used in the control rods of nuclear reactors as a neutron absorber. Atomic number 5; atomic weight 10.811; melting point 2,300°C; sublimation point 2,550°C; specific gravity (crystal) 2.34; valence 3. See Periodic Table.
Show More
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.