fluorine

noun

fluo·​rine ˈflu̇r-ˌēn 

ˈflȯr-

: a nonmetallic gaseous chemical element of the halogen group with atomic number 9 that readily forms compounds with almost all other elements including some noble gases see Chemical Elements Table

Examples of fluorine in a Sentence

Recent Examples on the Web

In the conversion process, the solid uranium oxide concentrate is reacted with fluorine to create the UF6 gas. —Aman Tripathi, Interesting Engineering, 27 Mar. 2026

The front glass also includes an anti-smudge coating, fluorine, a material that repels grease and moisture. —Jim Fisher, PC Magazine, 16 Mar. 2026

The researchers also flagged some samples with small traces of fluorine, a chemical that can lead to lower birth rates in high doses, as well as organohalogens and nitroaromatics—both known to have carcinogenic effects. —Aude Konan, Scientific American, 11 Feb. 2026

Because of the low reactivity of fluorine, when KL-50 deposits fluoroethyl groups onto the cells, the crosslinks are slow to form. —Isabella Backman, Hartford Courant, 27 Jan. 2026

Word History

Etymology

French, from New Latin fluor

First Known Use

1813, in the meaning defined above

Rhymes for fluorine

• agin
• alkene
• allene
• ameen
• amin
• amine
• arene
• athene
• baleen
• beeline
• benzene
• between

Kids Definition

fluorine

noun

flu·​o·​rine

ˈflu̇(-ə)r-ˌēn, 

-ən

: a nonmetallic element that is normally found alone as a pale yellowish flammable irritating poisonous gas having two atoms per molecule see element

Medical Definition

fluorine

noun

fluo·​rine ˈflu̇(-ə)r-ˌēn  -ən 

: a nonmetallic monovalent halogen element that is normally a pale yellowish flammable irritating toxic gas

—symbol F see Chemical Elements Table