Diary/ˈdaɪəri/ Definition 1 of 3Pro Tip 1/3Personal Reflections Used for private thoughts, not shared with others. He reads his diary to reflect on personal growth. Pro Tip 2/3Emotional Release Often a space to express feelings freely. Her diary was full of joyous and sad moments. Pro Tip 3/3Consistency Counts Regular entries create a more valuable personal history. Daily diary writing has become part of my routine.