This is the 286th most frequent Vietnamese word.
dần
Gradually; slowly.
In this context, "dần" indicates progression or a gradual process.
Trời dần sáng.
The sky is gradually getting brighter.
Here, "dần" shows the slow development or acquisition of understanding.
Anh ấy dần hiểu ra sự việc.
He gradually understands the situation.
In this case, "dần" emphasizes the incremental progress towards achieving a goal.