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

Another problem is the illegal retrofitting of LED bulbs, especially when fitted into units designed for halogen.

From BBC • Feb. 18, 2026

"The resulting datasets are producing an improved understanding of the interactions between sea-spray aerosols, surface-coupled clouds, oil field emissions and multiphase halogen chemistry in the new Arctic."

From Science Daily • Dec. 29, 2025

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

When a simple halogen lamp illuminates the tiny cavities, the light inside is captured as if in a trap.

From Science Daily • Oct. 23, 2025

The danger bathed the world in a halogen glow that caused everything—the sweep of the rock, the orange and yellow lichens, the texture of the clouds—to stand out in brilliant relief.

From "Into the Wild" by Jon Krakauer

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