defibrillationPronunciation: /ˌdiːfɪbrɪˈleɪʃ(ə)n/Definition of defibrillation noun [mass noun] Medicine the stopping of fibrillation of the heart by administering a controlled electric shock, to allow restoration of the normal rhythm. Derivatives defibrillate verb defibrillation in other Oxford dictionaries Definition of defibrillation in the US English dictionary