Diaries are typically seen as a way to record your day. A journal, on the other hand, is viewed more as a way to reflect on your day.
For many people, they are the same or may sound the same, but they are quite different. A diary is typically a notebook where you keep a record of your day, the events that occurred during that day, and even your thoughts on those events. Journaling is when you actually reflect on these things.
When you journal, you may also write down events that occurred during your day, but the purpose is to actually write down your thoughts, feelings, and emotions about those events. You write them down to better understand them, so you take the time to actually think about them and reflect on them.
