In royal families, the crown goes to the oldest child. That's theheir. The "spare heir" is the next child who would ascend thethrone should something happen to the heir. In the UK, whenWilliam becomes King, Prince George is the heir. His brother orsister, who will be born in April, will be William's spare heir. Harrywas the spare heir until Prince George was born.
在王室中,王位傳給長子,稱作王位繼承人。如果王位繼承人發(fā)生不測,下一個繼承王位的人叫做備胎繼承人。在英國,當(dāng)威廉王子成為國王時,喬治王子就是王位繼承人,而即將在4月出世的二胎,無論男女,都會成為威廉的備胎繼承人。在喬治王子出生之前,威廉的弟弟哈里王子一直是備胎繼承人。
For example:
Aristocratic wives were once told they needed to provide an "heir and a spare heir" at least.
貴族的妻子們曾經(jīng)被教導(dǎo)要至少生一個繼承人和一個備胎繼承人。