Heir, Heiress, Successor
noun
The traces are the people that inherit what you have. They are your heirs or heiresses. Your successor.
あとつぎ
The reading is the vocab words 跡 and 継ぐ put together.
父親が跡継ぎに弟を選んだという知らせは、彼にとって大きな打撃でした。
The news that his father chose his younger brother as his heir was a huge blow.