halogen

American  

[hal-uh-juhn, -jen, hey-luh-] / ˈhæl ə dʒən, -ˌdʒɛn, ˈheɪ lə- /

noun

Chemistry.

1. any of the electronegative elements, fluorine, chlorine, iodine, bromine, and astatine, that form binary salts by direct union with metals.

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halogen British  

/ ˈhæləˌdʒɛn, həˈlɒdʒɪnəs /

noun

1. any of the chemical elements fluorine, chlorine, bromine, iodine, and astatine. They are all monovalent and readily form negative ions

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halogen Scientific  

/ hăl′ə-jən /

1. Any of a group of five nonmetallic elements with similar properties. The halogens are fluorine, chlorine, bromine, iodine, and astatine. Because they are missing an electron from their outermost shell, they react readily with most metals to form salts.

2. See Periodic Table

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Other Word Forms

• halogenoid adjective
• halogenous adjective

Etymology

Origin of halogen

First recorded in 1835–45; halo- + -gen

Compare meaning

How does halogen compare to similar and commonly confused words? Explore the most common comparisons:

• halide vs. halogen

Example Sentences

This process allows researchers to control which halogen atoms, including chlorine, bromine, or iodine, attach to the surface.

From Science Daily • Apr. 4, 2026

The beam is whiter, more focused and brighter than the more diffuse light from halogen lamps fitted in older cars.

From BBC • Oct. 27, 2025

One already well-understood source of glare is drivers retrofitting their vehicles, replacing old halogen bulbs with LEDs.

From BBC • Oct. 27, 2025

However, the influence of halogen bonds on the rapid photoinduced changes within supramolecular systems remains largely unexplored due to a lack of experimental techniques that can directly observe the halogen bond in action.

From Science Daily • Jun. 4, 2024

As the broiling sun set, a different kind of American landscape lit up: The halogen floodlights from the truck stop could be seen for miles.

From "Geeks: How Two Lost Boys Rode the Internet Out of Idaho" by Jon Katz

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