fluorine Syllabification: (fluor·ine)Pronunciation: /ˈflo͝orˌēn, flôr-/Definition of fluorine noun the chemical element of atomic number 9, a poisonous pale yellow gas of the halogen series. It is the most reactive of all the elements, causing severe burns on contact with skin. (Symbol: F)Origin: early 19th century: from fluor (see fluorspar) + -ine4fluorine in other Oxford dictionaries Definition of fluorine in the British & World English dictionary
