from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A system using transmitted and reflected underwater sound waves to detect and locate submerged objects or measure the distance to the floor of a body of water.
- n. An apparatus, as one in a submarine, using sonar.
- n. Echolocation.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. echolocation
- n. A device that uses hydrophones (in the same manner as radar) to locate objects underwater.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. 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
so(und) na(vigation and) r(anging).(American Heritage® Dictionary of the English Language, Fourth Edition)