sonar
Americannoun
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a method for detecting and locating objects submerged in water by echolocation.
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the apparatus used in sonar.
noun
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Short for sound navigation and ranging. A method of detecting, locating, and determining the speed of objects through the use of reflected sound waves. A sound signal is produced, and the time it takes for the signal to reach an object and for its echo to return is used to calculate the object's distance. The Doppler effect can also be used to determine the object's relative velocity. Electronic sonar systems are used for submarine navigation and for detecting schools of fish. Some mammals, especially bats, use biological sonar to navigate and detect prey in dark conditions, commonly called echolocation.
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The equipment or physiology used in doing this.
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See also Doppler effect lidar radar
Etymology
Origin of sonar
1940–45; so(und) na(vigation) r(anging)
Compare meaning
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Explanation
Sonar is a method of finding objects under water using sound waves. If the Titanic had been able to use sonar, it never would have hit that iceberg. There are two kinds of sonar: active sonar, which sends sounds out and listens for their echoes, and passive sonar, which records existing sounds. Both allow boat and submarine pilots, explorers, the military, and scientists to determine how far away underwater objects are and approximately how large they are. Leonardo da Vinci gets the credit for inventing sonar when he inserted a tube in the water and listened for the sound of distant ships in 1490.
Vocabulary lists containing sonar
Earth Science - Middle School
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Earth Science - High School
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Earth Science - Introductory
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
"Using seismic waves from earthquakes, we can create a slice-through image of the lithosphere, much like a sonar can pick out features on the seabed," said Professor Sergei Lebedev, a geophysicist involved in the study.
From Science Daily • May 26, 2026
The bass society limits sonar users to one transducer, while viewing screens can’t have a diameter of more than 55 inches.
From The Wall Street Journal • May 5, 2026
They use sonar to scan the bottom of the ocean for mines without putting sailors at risk.
From The Wall Street Journal • Apr. 19, 2026
The team says this is the first time sonar mapping and satellite imagery have been brought together in this way to examine Lough Neagh and "attempt to quantify the range of potential impacts".
From BBC • Apr. 15, 2026
The torturous ping of enemy sonar waves echoed relentlessly through the boat.
From "Fallout: Spies, Superbombs, and the Ultimate Cold War Showdown" by Steve Sheinkin
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
