/ ˈflɔːriːn; NAmE ; BrE also ˈflʊər-; NAmE also ˈflʊr-/ noun
[ U ] ( symb F ) a chemical element. Fluorine is a poisonous pale yellow gas and is very reactive .
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WORD ORIGIN
early 19th cent.: from fluor a flow, a mineral used as a flux, fluorspar (from Latin fluor , from fluere to flow) + -ine .