a white inert crystalline solid existing both in a graphite-like form and in an extremely hard diamond-like form(borazon). It is used as a refractory, high-temperature lubricant and insulator, and heat shield. Formula: BN
boron nitride in American English
a white, powdery compound, BN, of boron and nitrogen, with high electrical resistance: it can be compressed, under a million pounds of pressure, to form Borazon