Red Cross? (6,3,6)
I believe the answer is:
hammer and sickle
This clue could be a double definition.
'red' is the first definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'cross?' is the second definition.
(thesaurus)
Can you help me to learn more?
(Other definitions for hammer and sickle that I've seen before include "that's symbolic for Left" , "revolutionary tools" .)