Meaning of SONAR in English

SONAR

[noun] [U] - equipment, esp. on a ship, which uses sound waves to discover how deep the water is or the position of an object in the water, such as a group of fish(figurative) Bats have a sort of built-in sonar to help them find their way in the dark.

Cambridge English vocab.      Кембриджский английский словарь.