diary

noun

di·​a·​ry ˈdī-(ə-)rē 

plural diaries

1

: a record of events, transactions, or observations kept daily or at frequent intervals : journal

especially : a daily record of personal activities, reflections, or feelings

2

: a book intended or used for a diary

Synonyms

• journal

Examples of diary in a Sentence

has diligently kept a diary since she was 15

Recent Examples on the Web

Long before the video diary became the en vogue format of personal expression on YouTube and social media platforms like TikTok, Ross McElwee was America’s preeminent first-person filmmaker. —Vikram Murthi, IndieWire, 3 Sep. 2025

Keep notes in your diary, journal about your dreams and pay attention to your surroundings. —Valerie Mesa, People.com, 2 Sep. 2025

But the new book claims to have access to 17 of his diaries and an interview with his secret love child. —Chloe Mayer, MSNBC Newsweek, 1 Sep. 2025

Sleep duration and midpoint were calculated daily with sleep diaries. —New Atlas, 24 Aug. 2025

Word History

Etymology

Latin diarium, from dies day — more at deity

First Known Use

1581, in the meaning defined at sense 1

Phrases Containing diary

• keep a diary

Rhymes for diary

• fiery
• friary
• priory

Kids Definition

diary

noun

di·​a·​ry ˈdī-(ə-)rē 

plural diaries

: a daily record especially of personal experiences and thoughts

also : a book for keeping such a record

Etymology

from Latin diarium "a record of business dealings or activities during the day," from dies "day" — related to meridian, sunday see Word History at sunday