Rydberg atom Syllabification: (Ryd·berg at·om)Pronunciation: /ˈridˌbərg/Definition of Rydberg atom noun Physics an atom in a highly excited state in which one electron has almost sufficient energy to escape. Atoms, usually hydrogen atoms, in this Rydberg state are used in atomic research. Origin:named after J. R. Rydberg (see Rydberg constant)Rydberg atom in other Oxford dictionaries Definition of Rydberg atom in the British & World English dictionary