ultrasound

[uhl-truh-sound]

noun

1. Physics.,  sound with a frequency greater than 20,000 Hz, approximately the upper limit of human hearing.

2. Medicine/Medical.,  the application of ultrasonic waves to therapy or diagnostics, as in deep-heat treatment of a joint or imaging of internal structures.

ultrasound

/ ˈʌltrəˌsaʊnd /

noun

1. ultrasonic waves at frequencies above the audible range (above about 20 kHz), used in cleaning metallic parts, echo sounding, medical diagnosis and therapy, etc

ultrasound

1. Sound whose frequency is above the upper limit of the range of human hearing (approximately 20 kilohertz).

2. See ultrasonography

3. An image produced by ultrasonography.

ultrasound

1. A method of diagnosing illness and viewing internal body structures in which sound waves of high frequency are bounced off internal organs and tissues from outside the body. The technique measures different amounts of resistance the body parts offer to the sound waves, and then uses the data to produce a “picture” of the structures. Ultrasound is often used to obtain an image of the developing fetus in pregnant women; the image can confirm the presence of twins or triplets and can be used to diagnose some abnormalities.

When an image of the inside of the body is needed, ultrasound is often considered a safer alternative to x-rays. Like x-rays, ultrasound involves exposure of the body to a form of radiation; unlike x-rays, ultrasound has not been shown to be carcinogenic.

Word History and Origins

Origin of ultrasound¹

First recorded in 1920–25; ultra- + sound ¹

A Closer Look

Many people use simple ultrasound generators. Dog whistles, for example, produce tones that dogs can hear but that are too high to be heard by humans. Sound whose frequency is higher than the upper end of the normal range of human hearing (higher than about 20,000 hertz) is called ultrasound. (Sound at frequencies too low to be audible—about 20 hertz or lower—is called infrasound.) Medical ultrasound images, such as those of a fetus in the womb, are made by directing ultrasonic waves into the body, where they bounce off internal organs and other objects and are reflected back to a detector. Ultrasound imaging, also known as ultrasonography, is particularly useful in conditions such as pregnancy, when x-rays can be harmful. Because ultrasonic waves have very short wavelengths, they interact with very small objects and thus provide images with high resolution. For this reason ultrasound is also used in some microscopes. Ultrasound can also be used to focus large amounts of energy into very small spaces by aiming multiple ultrasonic beams in such a way that the waves are in phase at one precise location, making it possible, for example, to break up kidney stones without surgical incision and without disturbing surrounding tissue. Ultrasound's industrial uses include measuring thicknesses of materials, testing for structural defects, welding, and aquatic sonar.

Example Sentences

She posted a series of pictures of the two of them on social media, including a shot of an ultrasound and video of her getting the scan done.

From Los Angeles Times

Participants are given a five-hour appointment to be scanned using five different types of MRI, X-ray and ultrasound machines.

From BBC

Her family had no choice in that decision; state law grants fetuses personhood and bans abortion after the point at which an ultrasound can detect cardiac activity in an embryo.

From Salon

The American College of Obstetricians and Gynecologists does not recommend this approach, advising doctors instead to review the ultrasound as one piece of information among many and counsel patients on all their options.

From Salon

An MRI, further ultrasounds and biopsies revealed she had Stage 1 invasive cancer, and Munn underwent a double mastectomy.

From Los Angeles Times