View your list of saved words. (You can log in using Facebook.)
About Our Definitions: All forms of a word (noun, verb, etc.) are now displayed on one page.
Definition of ULTRASOUND
: vibrations of the same physical nature as sound but with frequencies above the range of human hearing
: 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
Use of ultrasonic waves to produce images of body structures. The waves travel through tissues and are reflected back where density differs (e.g., the border between a hollow organ's wall and its inside). The reflected echoes are received by an electronic apparatus that measures their intensity level and the position of the tissue reflecting them. The results can be displayed as still images or as a moving picture of the inside of the body. Unlike X-rays or other ionizing radiation, ultrasound carries minimal, if any, risk. Most often used during pregnancy to examine the fetus, ultrasound imaging is also used on internal organs and on the eye, breast, and major blood vessels. It can often show whether a growth is benign or malignant. See alsodiagnostic imaging.