diary

UK: /ˈdaɪəri/ US: /ˈdaɪəri/ ,(dī′ə rē)

Inflections of 'diary' (n): npl: diaries

WordReference Random House Learner's Dictionary of American English © 2025

di•a•ry /ˈdaɪəri/   n. [countable] , pl. -ries. 

1. a daily written record of one's observations and feelings:
   Keep a diary of everyday happenings.
2. a book for keeping such a record:
   She wrote in her diary.
3. a book for noting daily appointments:
   I've checked my diary and I'm free next week.

di•a•rist /ˈdaɪrɪst/  n. [countable]

WordReference Random House Unabridged Dictionary of American English © 2025

di•a•ry  (dī′ə rē), n., pl. -ries. 

1. a daily record, usually private, esp. of the writer's own experiences, observations, feelings, attitudes, etc.
2. a book for keeping such a record.
3. a book or pad containing pages marked and arranged in calendar order, in which to note appointments and the like.

• Latin diārium daily allowance, journal, equivalent. to di(ēs) day + -ārium -ary
• 1575–85

Synonyms

• 1, 2. journal, daybook, log, chronicle.

Collins Concise English Dictionary © HarperCollins Publishers::

diary / ˈdaɪərɪ/ noun ( -ries)

1. a personal record of daily events, appointments, observations, etc
2. a book for keeping such a record

Etymology: 16th Century: from Latin diārium daily allocation of food or money, journal, from diēs day