Vision (Definition) Vision is a feature of a person's brain that allows him to see. He must have normal eyes, optic nerves (that stretch from the eyes to the back of his brain), and visual cortex (the vision center in the brain), in order to see properly. An ophthalmologist is a doctor specializing in vision. ...Read more.
The halogens or halogen elements (/ËhÃ¦lÉdÊÉn, ËheÉª-, -loÊ-, -ËdÊÉn/) are a group in the periodic table consisting of five chemically related elements: fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). The artificially created element 117 (ununseptium) may also be a halogen.
Medical Definition of HALOGEN. : any of the five elements fluorine, chlorine, bromine, iodine, and astatine that form part of group VII A of the periodic table and exist in the free state normally as diatomic molecules.â haÂ·logÂ·eÂ·nous \ha-Ëlaej-ËlÃ¤j-É\ nÉs. adjective any of the five elements fluorine, chlorine, bromine, iodine, and astatine that form part of group VIIA of the periodic table and exist in the free state normally as diatomic molecules. â haÂ·logÂ·eÂ·nous \ha-Ëlae-ËlÃ¤-jÉ\ nÉs. Adjective see halogen defined for. kids