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that part of the science of acoustics dealing with the frequency range beyond the upper limit of perception by the human ear, i.e. above 20,000 hertz (cycles per second), but usually restricted to frequencies above 50,000 hertz. Ultrasonic radiation is injurious to tissues because of its thermal effects when absorbed by living matter, but in controlled doses it can be used therapeutically to selectively break down pathologic tissues, as in treatment of arthritis and lesions of the nervous system, and also as a diagnostic aid by visually displaying echoes received from irradiated tissues, as in echocardiography. See also ultrasonography.
The science and technology of ultrasound, its characteristics and phenomena.
n. (used with a sing. verb)
1. The acoustics of ultrasonic sound.
2. The science and technology that deals with the study and application of ultrasound.
The science and technology of ultrasound, its characteristics, and its phenomena.