Source : Webster's Revised Unabridged Dictionary (1913)

Boron \Bo"ron\ (b[=o]"r[o^]n), n. [See {Borax}.] (Chem.)
   A nonmetallic element occurring abundantly in borax. It is
   reduced with difficulty to the free state, when it can be
   obtained in several different forms; viz., as a substance of
   a deep olive color, in a semimetallic form, and in colorless
   quadratic crystals similar to the diamond in hardness and
   other properties. It occurs in nature also in boracite,
   datolite, tourmaline, and some other minerals. Atomic weight
   10.9. Symbol B.

Source : WordNet®

boron
     n : a trivalent metalloid element; occurs both in a hard black
         crystal and in the form of a yellow or brown powder [syn:
          {B}, {atomic number 5}]