DIARY

[noun] [C] - a book with a separate space or page for each day, in which you write down your future arrangements, meetings, etc. or in which you record anything of interest that has happened to you during the day, together with your thoughts or feelings that you have at the timeI'd better note the date of the meeting down in my diary or I'll forget it.I've never kept (= written about what has happened to me in) a diary.