diary Definition

diary
noun diaries

1a. A written record of daily events in a person's life;

Thesaurus: journal, log, record, chronicle, day book.
1b. A book containing this.
(Brit)
2. A book with separate spaces or pages for each day of the year in which appointments, daily notes and reminders may be written.

Thesaurus: appointment book, engagement book.

Etymology: 16c: from Latin diarium, from dies day.