TV detective's cipher (5)
I believe the answer is:
morse
This clue could be a double definition.
'tv detective's' is the first definition.
(I've seen this before)
'cipher' is the second definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for morse that I've seen before include "Fictional inspector; code" , "Code inventor, Samuel" , "Kind of code" , "Radio code inventor" , "Colin Dexter's fictional detective" .)