1. Sound waves with frequencies below the lower limit of human hearing, typically below 20 hertz.
Usage: plural form of infrasound; technical/scientific term; also called subsonic sound

Examples

• Infrasounds produced by earthquakes can travel vast distances through the Earth.
• Whales communicate using infrasounds that travel hundreds of miles underwater.
• Scientists study infrasounds generated by volcanic eruptions to predict future activity.
• Some animals, like elephants, can detect infrasounds that humans cannot hear.
• The infrasounds from the storm were felt as vibrations rather than heard as sound.
• Research shows that infrasounds may affect human physiology in subtle ways.