(aviation) A type of airline that tries to keep ticket prices as low as possible, by charging for everything, such as checked-in baggage, carry-on baggage, food, beverages, assigned seat numbers, etc.

plural of ultra low cost carrier

(acoustics) Beyond (higher in frequency than) the range of sound perceptible to the human ear; with a frequency of 20 kilohertz or higher.

(physics) Sound with a frequency greater than the upper limit of human hearing, which is approximately 20 kilohertz. / (medicine) The use of ultrasonic waves for diagnostic or therapeutic purposes.

(transitive, intransitive) To treat with ultrasound.

the science and technology of ultrasound

(laboratory, deprecated label) A piece of industrial or laboratory equipment that consists of a container, or bath, used for cleaning, mixing, or homogenisation of objects or substances by sending ultrasonic vibrations through the liquid contained in it.

(uncountable) A medical ultrasound technique, used, for example, during pregnancy, providing three-dimensional-looking flat images. / (countable) An image so produced.

(uncountable) A medical ultrasound technique that produces a sequence of 3D images over time. / (countable) An image so produced.

extremely safe.