/ ˈdaɪəri; NAmE / noun ( pl. -ies )
1.
( BrE ) ( NAmE date·book ) a book with spaces for each day of the year in which you can write down things you have to do in the future :
a desk diary
I'll make a note of our next meeting in my diary.
2.
a book in which you can write down the experiences you have each day, your private thoughts, etc. :
Do you keep a diary (= write one regularly) ?
—see also journal , video diary ➡ note at agenda
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WORD ORIGIN
late 16th cent.: from Latin diarium , from dies day.