Definition of "infrasound" [infrasound]

• A wave phenomenon sharing the physical nature of sound but with a range of frequencies below that of human hearing. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "And I recall from my army papers, that internal organs have their resonating frequencies, but they are generally in infrasound range."
• "The AGNIR report also looks at the available evidence for the health effects of infrasound, which is produced by aircraft, trains and other machines, as well as thunderstorms, wind and waves."
• "More importantly, and speaking of porn, is there a kind of infrasound that can generate sudden and uncontrollable sexual arousal?"