[ 'halədʒ(ə)n , 'heɪl- ]
■ noun
1》 Chemistry any of the group of reactive non-metallic elements fluorine, chlorine, bromine, iodine, and astatine.
2》 [as modifier ] denoting lamps and radiant heat sources using a filament surrounded by ~ vapour.
Derivatives
~ic adjective
Origin
C19: from Gk hals , halo- 'salt' + -gen .