ultrasound Syllabification: (ul·tra·sound)Pronunciation: /ˈəltrəˌsound/Translate ultrasound | into French | into German | into Italian | into Spanish Definition of ultrasound noun sound or other vibrations having an ultrasonic frequency, particularly as used in medical imaging. an ultrasound scan, especially one of a pregnant woman to examine the fetus. ultrasound in other Oxford dictionaries Definition of ultrasound in the British & World English dictionary