sonobuoy
/ˈsɑnoʊbɔɪ/
noun
- A floating device dropped from aircraft or ships that detects underwater sounds, such as those from submarines, and sends the information to a receiver.
- The navy deployed a sonobuoy to listen for enemy submarines in the area.
- The helicopter dropped a sonobuoy into the ocean to track the underwater vehicle.
- Researchers used a sonobuoy to record the calls of whales migrating along the coast.