An outstanding feature of the unicorn (4)
I believe the answer is:
horn
This clue could be a double definition.
'an outstanding feature' is the first 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?
'the unicorn' is the second definition.
Although both the answer and definition are singular nouns, I cannot understand how they can define each other.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for horn that I've seen before include "Instrument - rhino's feature" , "Musical instrument - antler" , "Hooter" , "See 1 Across" , "Brass musical instrument" .)