Pronunciation GB: ˌeɪpɪəriˈɒdɪk, GA: ˌeɪpɪriˈɑdɪk

Of a waveform: not regularly repeating. Voiceless fricatives, for instance, display an aperiodic waveform. See the illustration below, which is a portion waveform of the utterance she in English. The end of the [ʃ] and the start of the [iː] are displayed.