A diary is a written or audiovisual memorabilic record, with discrete entries arranged by date reporting on what has happened over the course of a day or other period. Diaries have traditionally been handwritten but are now also often digital. A personal diary may include a person's experiences, thoughts, and/or feelings, excluding comments on current events outside the writer's direct experience. Someone who keeps a diary is known as a diarist. Diaries undertaken for institutional purposes play a role in many aspects of human civilization, including government records, business ledgers, and military records. In British English, the word may also denote a preprinted journal format.

दैनन्दिनी या डायरी एक पुस्तक है जिसमें एक व्यक्ति अपने जीवन में घटनाओं और अनुभवों का दैनिक अभिलेख रखता है।