1. a grey tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons; [syn: hafnium, Hf, atomic number 72]
WordNet (r) 3.0 (2006):
atomic number 72
n 1: a grey tetravalent metallic element that resembles
zirconium chemically and is found in zirconium minerals;
used in filaments for its ready emission of electrons [syn:
hafnium, Hf, atomic number 72]