Radiotelegraphy code (5)
I believe the answer is:
'radiotelegraphy code' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for morse that I've seen before include "10 [SLEUTH]" , "Oxford detective" , "& 24 Across Encrypted language" , "used to transmit messages" , "Code inventor, Samuel" .)