echo sounder vs asdic

echo sounder and asdic both are nouns.

Word	Noun	Adjective	Verb	Adverb
echo sounder	Yes	No	No	No
asdic	Yes	No	No	No

As nouns, echo sounder and asdic are synonyms defined as:

echo sounder and asdic: 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

Other synonyms of echo sounder include sonar.

echo sounder (noun)	asdic (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	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