halogen
Americannoun
noun
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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.
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See Periodic Table
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Explanation
A halogen is a chemical element that forms a salt when it reacts with metal. Halogen lamps are illuminated by bulbs that contain a halogen and an inert gas. There are five halogens in the periodic table of chemical elements: fluorine, chlorine, bromine, iodine, and astatine. The halogens are all highly reactive, which means they're quick to form bonds with other elements. What they often end up becoming is some kind of salt, including common table salt. In fact, the literal translation of halogen is "salt-producer," from Greek roots hals, "salt," and gen, "giving birth to."
Vocabulary lists containing halogen
Chemistry - High School
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Structure and Properties of Matter - High School
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
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He did a more-than-competent job—he was Rossini after all—but the result always reminds me of shining a halogen light into a place of hallowed dim.
From The Wall Street Journal ● May 15, 2026
Also, LED lights "are a lot more directional, so you've got this much brighter, whiter light in a very directional point hitting your eye compared to the more diffuse halogen ones".
From BBC ● Feb. 18, 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
When illuminated by the microscope's halogen lamp and analyzed through a spectrometer, the light separates into different wavelengths.
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
Firstly, they are two to three times as bright as traditional halogens, and their "colour temperature" is bluer and whiter, which mimics natural daylight.
From BBC ● Feb. 18, 2026
Researchers also found that halogens interact with oil field emissions to form free radicals, which later become more stable compounds capable of traveling long distances.
From Science Daily ● Dec. 29, 2025
A team from France and Germany has now studied the rapid decay of molecules containing halogens.
From Science Daily ● Dec. 2, 2024
The oxides of halogens, at least one of the noble gases, and metals with higher reduction potentials than copper do not form by the direct action of the elements with oxygen.
From Textbooks ● Feb. 14, 2019
Compounds of silicon with hydrogen and the halogens.
From An Elementary Study of Chemistry by McPherson, William
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
