diary

Concise Oxford English Dictionary © 2008 Oxford University Press:
diary/ˈdʌɪəri/

▶noun (pl. diaries) a book in which one keeps a daily record of events and experiences.

■ Brit. a book with spaces for each day of the year in which to note appointments.

word history: As well as being synonyms, diary and journal come from the same Latin word, dies ‘day’. The older word journal came into English in the 14th century from Old French jurnal, from Latin diurnalis ‘daily’; the later word diary, which entered English in the 16th century, came directly from Latin diarium ‘daily allowance’, later ‘diary’. dial and dismal also derive from dies, the latter being a contraction of dies mali ‘evil days’.