[ in-fruh-sound ]
/ ˈɪn frəˌsaʊnd /


sound with frequencies below the audible range.

Origin of infrasound

First recorded in 1925–30; infra- + sound1 Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for infrasound


/ (ˈɪnfrəˌsaʊnd) /


soundlike waves having a frequency below the audible range, that is, below about 16Hz

Derived Forms

infrasonic (ˌɪnfrəˈsɒnɪk), adjective
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for infrasound


[ ĭnfrə-sound′ ]

Sound whose wave frequency is too low (under 15-20 hertz) to be heard by humans. Some animals, such as elephants and whales, emit calls at infrasound frequencies. See Note at ultrasound.

Related forms

infrasonic adjective
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.