[French iode, iodine, from Greek iōdēs, violet-coloured.]
The element iodine was so named from the colour of its vapour. In medicine, iodism is iodine poisoning; iodopsin is a photosensitive violet pigment that occurs in the cones of the retina; an iodophor (Greek pherein, to bear) is one of a group of disinfectants containing iodine in combination with a detergent. A compound that has been iodinated has had iodine introduced into it; iodides are compounds of iodine with another element or group. The form is used in names of organic compounds containing the radical —I, for example iodobenzene or iodoform, a yellow crystalline compound with antiseptic properties.