sonar

/sou'nɑ:/
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sonar

A research vessel uses sonar to map the ocean floor.

Definition
  1. Noun:
    • A measuring instrument that sends out an acoustic pulse in water and measures distances based on the time for the echo to return: "Sonar" is a device used to detect and locate objects underwater by emitting sound waves and analyzing their reflections.
    • The technology or system based on this principle: "Sonar" can also refer to the general method or technique of underwater detection and navigation using sound.
Usage Examples
  • Noun:
    • The submarine used its sonar to navigate safely through the dark depths.
    • Marine biologists use sonar to map the ocean floor and study whale migrations.
    • The ship's sonar detected an object several hundred meters below.
Advanced Usage
  • "Active sonar": A type of sonar that emits a pulse of sound (a "ping") and listens for its echo. It is used for precise detection but can reveal the user's location.

    • The navy vessel used active sonar to search for the wreckage.
  • "Passive sonar": A type of sonar that only listens for sounds made by other objects, such as ship propellers or marine life. It is used for stealthy detection.

    • The submarine relied on passive sonar to avoid detection while monitoring enemy ships.
Variants and Related Words
  • ASDIC (noun): An older term, primarily British, for sonar technology used in anti-submarine warfare. It is an acronym for "Anti-Submarine Detection Investigation Committee."

    • The historical documentary explained the development of ASDIC during World War II.
  • Echolocation (noun): The biological process used by animals like bats and dolphins to navigate and hunt by emitting sounds and interpreting the echoes. It is the natural counterpart to sonar.

    • Dolphins' echolocation is remarkably similar to the principle of man-made sonar.
Synonyms
  • Echo sounder: A device for determining water depth by measuring the time of an echo.
  • Sound navigation and ranging: The full phrase from which the acronym "sonar" is derived.
Related Phrases
  • Sonar buoy (noun phrase): A floating buoy equipped with sonar, often deployed from aircraft to detect submarines.

    • The patrol plane dropped a sonar buoy to listen for submarine activity.
  • Sonar image (noun phrase): A visual representation, like a map or scan, created from processed sonar data.

    • The sonar image revealed the detailed shape of the sunken ship.
Notes on Meaning
  • Acronym: The word "sonar" is an acronym for Sound Navigation and Ranging. This origin is key to understanding its function.
  • Primary Context: While most associated with naval and marine applications, sonar technology is also used in fishing, underwater research, and even some medical imaging techniques.
sonar

A research vessel uses sonar to map the ocean floor.

Noun
  1. a measuring instrument that sends out an acoustic pulse in water and measures distances in terms of the time for the echo of the pulse to return
    • sonar is an acronym for sound navigation ranging
    • asdic is an acronym for antisubmarine detection investigation committee