Repeat code word (4)
I believe the answer is:
echo
This clue could be a double definition.
'repeat' is the first definition.
(I know that repeat can be written as echo)
'code word' is the second definition.
The answer and definition can be both related to communication as well as being singular nouns.
Maybe they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for echo that I've seen before include "Repetition of sound" , "Close imitation" , "Sound heard before" , "A natural sound reflection" , "copy" .)