Definition of hydrogen noun from the Oxford Advanced Learner's Dictionary



BrE BrE//ˈhaɪdrədʒən//
; NAmE NAmE//ˈhaɪdrədʒən//
[uncountable] (symbol H)
jump to other results
a chemical element. Hydrogen is a gas that is the lightest of all the elements. It combines with oxygen to form water. Word Originlate 18th cent.: coined in French from Greek hudro- ‘water’ + -genēs ‘-born, of a specified kind’, from gen- (root of gignomai ‘be born, become’, genos ‘a kind’).
See the Oxford Advanced American Dictionary entry: hydrogen