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
Word origin
C19: from bor(ax) + (carb)on
boron in American English
(ˈbɔrˌɑn)
noun
a nonmetallic chemical element occurring only in combination, as with sodium and oxygen in borax, and produced in the form of either a brown amorphous powder or very hard,brilliant crystals: its compounds are used in the preparation of boric acid, water softeners, soaps, enamels, glass, pottery, etc.: symbol, B; at. no., 5
Word origin
< earlier boracium (< borax) + -on, as in carbon: so named by Davy, who isolated it (1808)
Examples of 'boron' in a sentence
boron
Inside were the bones, muscles and tendons of boron and titanium.