Effect That Can Be Perceived in Sirens or Radar
This page is the CodyCross answer for the clue below from Earth, Group 5, Puzzle 4.
Question is: Effect That Can Be Perceived in Sirens or Radar
and the answer is: DOPPLER
Word Meaning:
DOPPLER — (medicine, by ellipsis, informal) Ellipsis of Doppler ultrasonography: Any of various types of ultrasonography that use the Doppler effect; especially, medical versions thereof.
Definitions from Wiktionary.