她在王位继承人顺位中排第三。

She's third in order of succession to the throne.

《牛津词典》

过去，第二副首相都被看成是王位的第二顺位继承人。

In the past, second deputy prime ministers have been considered second in line to the throne.

youdao

当她问到英国王位的第二顺位继承人是否可以亲吻他，威廉说到：“亲吧！”

When she asked the second-in-line to the throne for a kiss, he said: "Go for it!"

youdao

One of them,by the way,just about ten years ago, the Orleanist family suffered kind of an embarrassing reversal when one of the Orleanists, sort of the third in line if there was ever an Orleanist restoration of the throne,was arrested for burglary, as being an accessory for burglary in the Pyrenees-Orientales.

顺便说一说,在十年前,奥尔良家族遭受了令人尴尬的霉运,这些儿子中的一个,如果奥尔良家族复辟的话,可以说是第三顺位继承人,他因为盗窃被捕,在东比利牛斯省因为盗窃同谋被捕

耶鲁公开课 - 1871年后的法国课程节选