boron

American  

[bawr-on, bohr-] / ˈbɔr ɒn, ˈboʊr- /

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. B; 10.811; 5.

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boron British  

/ ˈbɔːrɒn /

noun

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

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boron Scientific  

/ bôr′ŏn′ /

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.

2. See Periodic Table

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Other Word Forms

• boronic
  adjective

Etymology

Origin of boron

1805–15; bor(ax ¹ ) + (carb)on

Example Sentences

See Examples For:

boron

China controls around 90% of the processing of many rare-earth elements and graphite, around 70% of lithium-ion battery production and at least 80% of the boron compounds the world needs, according to the companies.

From The Wall Street Journal ● Jun. 25, 2026

Plans are underway for a new lithium and boron mine at Rhyolite Ridge, approximately 30 miles southwest of Tonopah, in Nevada’s Silver Peak Range.

From Los Angeles Times ● Jun. 14, 2026

In the future it will fuse hydrogen and boron to create clean energy.

From The Wall Street Journal ● Mar. 28, 2026

For example, China supplies 97 percent of the EU's magnesium, used in hydrogen-generating electrolysers while Turkey provides 99 percent of the bloc's boron, used in solar panels.

From Barron's ● Feb. 2, 2026

At the Cavendish, gold resisted the disintegration effect, except for a modest result the scientists traced to contamination of the heavier targets by light impurities such as boron.

From "Big Science" by Michael Hiltzik