English Reference

Word

fluorine

Phoneticsflu·o·rine

US/ˈfɫɔˌɹin/

UK/flˈɔːɹiːn/

Definition

n. a very active, greenish-yellow gas that is the most reactive of all the chemical elements. It is used to make things like toothpaste and plastic.

n. a highly reactive, pale yellow-green diatomic gas with the atomic number 9. It is the most electronegative and reactive of all the chemical elements, typically existing in a gaseous state at standard temperature and pressure.

Examples

“Fluorine is used to make certain types of plastic.”

“The chemist handled the fluorine gas with extreme care because it reacts violently with almost any other substance.”

“As the lightest halogen, fluorine exhibits unique properties that make it essential for the synthesis of pharmaceuticals and high-performance materials, though its extreme reactivity requires specialized containment.”

Examples

simple

“Fluorine is used to make certain types of plastic.”

contextual

“The chemist handled the fluorine gas with extreme care because it reacts violently with almost any other substance.”

complex

“As the lightest halogen, fluorine exhibits unique properties that make it essential for the synthesis of pharmaceuticals and high-performance materials, though its extreme reactivity requires specialized containment.”

Real-World Examples

“In these particles, ytterbium and erbium ions were embedded in a host matrix made of sodium, yttrium and fluorine, like chocolate chips in a cookie.”
Phys.org · 14 Sept 2026
“The researchers studied 3-fluoropyridine, a small ring-shaped molecule containing both nitrogen and fluorine atoms.”
ScienceDaily · 30 Jul 2026

Etymology

From Latin fluor (“flow”) + -ine. Coined by British chemist Humphry Davy in 1813.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

Word family

fluorideNounfluorineNoun

Domain

Chemistry

This entry

Level
C1 · Advanced
Frequency
Occasional
Updated

Scan code

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English Reference