HF

Noun	1.	Hf - a gray tetravalent metallic element that resembles zirconium chemically and is found in zirconium minerals; used in filaments for its ready emission of electrons Synonyms: atomic number 72, hafnium
	2.	HF - 3 to 30 megahertz Synonyms: high frequency

Have Fun (telecommunication-slang, Usenet, IRC)atomic number 72, hafnium, metal, metallic element