Manner of speaking (or writing) (4)
I believe the answer is:
tone
I believe this is a double definition.
'manner of speaking' is the first definition.
(tone is a kind of manner of speaking)
'writing' is the second definition.
(tone is a kind of writing)
(Other definitions for tone that I've seen before include "Quality of a person's voice" , "A pitch of note" , "Theobald Wolf . . . ." , "Bodily firmness" , "Note as in voice" .)