n.
Pronunciation: ' ə l-tr ə - ˌ sau ̇ nd
Function: noun
Date: 1923
1 : vibrations of the same physical nature as sound but with frequencies above the range of human hearing
2 : the diagnostic or therapeutic use of ultrasound and especially a noninvasive technique involving the formation of a two-dimensional image used for the examination and measurement of internal body structures and the detection of bodily abnormalities ― called also sonography
3 : a diagnostic examination using ultrasound