Echo sounder and Echo-sounder

Echo sounder noun - 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.

Echo-sounder and echo sounder are semantically related. In some cases you can use "Echo-sounder" instead a noun phrase "Echo sounder".

Echo sounder and echo-sounder are semantically related. Sometimes you can replace phrase "Echo sounder" with "Echo-sounder", this phrases are similar.