1. Sound waves with frequencies below the lower limit of human hearing, typically below 20 hertz.
Usage: uncountable; technical term used in acoustics and physics

Examples

• Infrasound is produced by large animals such as elephants and whales to communicate over long distances.
• The earthquake generated infrasound that was detected by specialized equipment miles away.
• Researchers study infrasound to better understand how certain animals navigate and interact.
• Wind turbines can produce infrasound as a byproduct of their operation.
• Infrasound frequencies are too low for the human ear to perceive, but some people report feeling vibrations from them.