Halogen /(hăl"ō̇*jĕn)/

Hal·o·gen

Halogen

n.
  1. An electro-negative element or radical, which, by combination with a metal, forms a haloid salt; especially, chlorine, fluorine, bromine, and iodine; sometimes, also cyanogen. See Chlorine family, under Chlorine. (Chem.)