fluoride

American  

[floor-ahyd, flawr-, flohr-] / ˈflʊər aɪd, ˈflɔr-, ˈfloʊr- /

noun

Chemistry.

1. a salt of hydrofluoric acid consisting of two elements, one of which is fluorine, as sodium fluoride, NaF.

2. a compound containing fluorine, as methyl fluoride, CH 3 F.

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fluoride British  

/ ˈflʊəˌraɪd /

noun

1. any salt of hydrofluoric acid, containing the fluoride ion, F ^–

2. any compound containing fluorine, such as methyl fluoride

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fluoride Scientific  

/ flr′īd′ /

1. A compound containing fluorine and another element or radical. Fluorine combines readily with nearly all the other elements, except the noble gases, to form fluorides. In some countries, fluoride is added to the drinking water as a preventive measure against tooth decay.

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fluoride Cultural  

1. Any of a number of naturally occurring compounds of the element fluorine. Fluorides have been found to be effective in preventing tooth decay and are routinely added to drinking water in most jurisdictions.

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Etymology

Origin of fluoride

First recorded in 1820–30; fluor- + -ide ( def. )

Compare meaning

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

• fluorine vs. fluoride

Explanation

Fluoride is that ingredient in toothpaste that keeps tooth enamel strong and helps prevent cavities. Small amounts of fluoride are also present in tap water and certain foods and beverages. Fluoride is a naturally occurring mineral widely recognized for its oral health benefits. Fluoride is often added to toothpaste and mouthwash to help prevent tooth decay by making the enamel more resistant to acid attacks from bacteria and sugars. That’s why some communities add it to their water supply systems: Regular exposure to fluoride is generally considered important in maintaining oral hygiene. Fluoride is also found in tea, seafood, and some fruits and vegetables. Now that’s toothsome!

Example Sentences

At one point, in a reference to the actress's teeth, she asks: "Fluoride? What's that?"

From BBC • Apr. 14, 2025

Fluoride is one of the most interesting stories of public health improvement.

From Slate • Jan. 16, 2025

Fluoride protects teeth and its inclusion in small amounts in drinking water is considered one of the greatest public health achievements of the last century.

From Los Angeles Times • Nov. 3, 2024

Fluoride is one of the more abundant elements naturally found in drinking water and levels around 0.7mg per liter have been proven to reduce tooth decay.

From Salon • Nov. 8, 2023

Fluoride of aluminium melts with carbonate of soda to a clear bead, spreads by cooling, and appears then milk-white.

From A System of Instruction in the Practical Use of the Blowpipe Being A Graduated Course Of Analysis For The Use Of Students And All Those Engaged In The Examination Of Metallic Combinations by Anonymous