iodine: Meaning and Definition of

i•o•dine

1. a nonmetallic halogen element occurring at ordinary temperatures as a grayish-black crystalline solid that sublimes to a dense violet vapor when heated: used in medicine as an antiseptic. Symbol: I; at. wt.: 126.904; at. no.: 53; sp. gr.: (solid) 4.93 at 20°C.