Definitions

1. adjective

below the range of human hearing; having a frequency lower than 20 Hz

“The infrasonic rumble of the thunderstorm caused the windows to vibrate.”

2. noun

sound waves or vibrations with frequencies below 20 Hz

“The infrasonics in the music studio were causing problems with the equipment.”

3. adjective

relating to or involving sounds or vibrations with frequencies below 20 Hz

“Infrasonic waves were detected emanating from the underwater volcano.”