This is the 883rd most frequent Vietnamese word.
đạn
"Đạn" means "bullet" or "ammunition" in English.
In this sentence, "đạn" refers to a bullet, specifically as ammunition that is fired from a firearm.
Anh ấy đã bắn viên đạn cuối cùng.
He fired the last bullet.
Here, "đạn" is used as part of "đạn pháo", denoting a large explosive projectile often fired from artillery.
Đạn pháo đã phá hủy một căn nhà trên phố.
The artillery shell destroyed a house on the street.
In this context, "đạn" metaphorically indicates gunfire or the sounds of bullets being fired in general.