Definition
To be the person who is next in succession to become the monarch after the current ruler.
王位继承人
Upon the current king's death, his eldest son will be first in line to the throne.
现任国王去世后，他的长子将成为王位的第一顺位继承人。
Having no other legitimate heirs, she became first in line to the throne.
由于没有其他合法继承人，她成为了王位的第一顺位继承人。
After generations of royal succession, he found himself in line to the throne.
在经历了几代王室继承后，他成为了王位继承人。