Definition of "infrasonic" [infrasonic]

• Generating or using waves or vibrations with frequencies below that of audible sound. (adjective)

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.

• "However, technological advances are making it possible to develop WMD based on qualitatively new principles, such as infrasonic (acoustic), radiological (enhanced-radiation), or particle-beam weapons."
• "Although we cannot hear these "infrasonic" waves - which have frequencies ranging from 0. 01-10 Hz - we know they exist from acoustic recordings around the globe."
• "Georgia Tech's center is testing highly sensitive "infrasonic" microphones that pick up sounds whose frequencies are too low to be detected by the human ear."