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

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

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

Understanding the distinctive and highly directional nature of halogen bonds is crucial for crystal engineering and studying photoinduced structural deformations, which is key for the development of innovative photo-functional materials.

From Science Daily • Jun. 4, 2024

Luke held the door, and they both squinted into the bright halogen of the store.

From "We'll Fly Away" by Bryan Bliss

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