Definition of "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 (noun)

WordNet. Princeton University. 2010.

• "Establishment (ASEE), where he was involved with the development of asdic, an early form of sonar, and then for the Admiralty Signals Establishment (ASE)."
• "I mean I'm also thinking of Japanese and I guess, Idaho and so on from a manual differentiation there, but in so called normal times, if they exist, is there a flow of chassis for asdic or is it fairly steady?"