Diary (7)
'diary' is the definition.
(I know that diary can be written as journal)
This is all the clue.
(Other definitions for journal that I've seen before include "Daily written record" , "Magazine; diary" , "Personal record" , "Newspaper - diary" , "Periodical" .)
(Another definition for daybook that I've seen is " Ledger for recording transactions as they occur".)