DuckCorp Dico

Found one definition

1.                 From WordNet (r) 3.0 (2006):
                   
   
   
                   
                     
   Hf
       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]
       2: 3 to 30 megahertz [syn: high frequency, HF]