Answer - reflection (4)
I believe the answer is:
echo
I believe this is a double definition.
'answer' is the first definition.
(thesaurus)
'reflection' is the second definition.
(I know that echo is a type of reflection)
(Other definitions for echo that I've seen before include "Marked by heat" , "repetitive" , "A natural sound reflection" , "Let's hear it again for the Greek nymph who loved Narcissus in vain" , "Sound bouncing back" .)