Origin: Latin prefix ultra-
Ultrasonic has 2 different meanings across 1 category:
having frequencies above those of audible sound
"The technician used an ultrasonic scanner to detect tiny cracks in the engine block without making any noise that humans could hear."
Beyond (higher in frequency than) the range of sound perceptible to the human ear; with a frequency of 20 kilohertz or higher.
"The dog whistled an ultrasonic tone that was completely invisible and silent to our ears but perfectly clear to his hearing."