Sofar

 
Pronunciation: /ˈsəʊfɑː/
(also SOFAR)

noun

[mass noun]
  • a system in which the sound waves from an underwater explosion are detected and located by three or more listening stations, useful in determining the position at sea of survivors of a disaster.

Origin:

1940s: from So(und) f(ixing) a(nd) r(anging)