An exclusive right of inheritance belonging to the eldest son of a single set of parents.
Example:
Many of the world's monarchies descend by the principle of primogeniture.
Primogeniture arose in England following the Norman Conquest of 1066. The practice began as a means of ensuring that fiefs (that is, estates) would not be broken up among the sons of a vassal. Eventually the right of the eldest son to inherit all of his father's estate was written into law. Primogeniture was one of the English practices that Americans were eager to abolish once independence had been attained. Leading the campaign against it was Thomas Jefferson.