1. A group of five highly reactive nonmetallic elements (fluorine, chlorine, bromine, iodine, and astatine) that form salts when combined with metals.
Usage: Plural form; singular is 'halogen'.; Chemistry term commonly taught in secondary school.

Examples

• Chlorine and fluorine are halogens used in water treatment and toothpaste.
• The halogens are located in Group 17 of the periodic table.
• Halogens are known for their strong odors and reactivity with other elements.
• Iodine is one of the halogens essential for human health.
• Many disinfectants contain halogens because of their antimicrobial properties.