sonar

noun

Etymology: By anacronymic evolution from SONAR.

1. Artificial echolocation by use of electronic equipment, with hydrophones to locate objects underwater, using the same wave-analysis principles that radar uses.

   “They were able to detect the sunken wreck using sonar.”

2. A device that provides such echolocation.

   “They finally bought a new sonar to replace the 40-year-old unit that sometimes didn't work right.”

3. Any echolocation.

   “Submarines and bats both use sonar to navigate.”