Wiktionary
ultimogeniture
n. A system of inheritance in which the youngest son or youngest child inherits an estate.
Wikipedia
Ultimogeniture
Ultimogeniture, also known as postremogeniture or junior right, is the tradition of inheritance by the last-born of the entirety of, or a privileged position in, a parent's wealth, estate or office. The tradition has been far rarer historically than primogeniture (sole inheritance by the first-born) or partible inheritance (division of the estate among the children).
Usage examples of "ultimogeniture".
And in daily life the women owned the households, and would pass them on to their youngest daughters: ultimogeniture, Ariadne called it, a custom of the Hopi.