1. a trivalent metalloid element; occurs both in a hard black crystal and in the form of a yellow or brown powder; [syn: boron, B, atomic number 5]
WordNet (r) 3.0 (2006):
atomic number 5
n 1: a trivalent metalloid element; occurs both in a hard black
crystal and in the form of a yellow or brown powder [syn:
boron, B, atomic number 5]