The character of one's correspondence? (6)
I believe the answer is:
letter
This could be a double definition.
'the character' is the first definition.
(letter is a kind of character)
'one's correspondence?' is the second definition.
'letter' can be an answer for 'correspondence?' (I've seen this before). I'm not sure about the 'one's' bit.
'of' acts as a link.
Can you help me to learn more?
(Other definitions for letter that I've seen before include "Alphabetic character" , "Written character - landlord" , "reference?" , "Alphabetic symbol" , "Character; missive" .)