Junior right
Black's Law Dictionary · Henry Campbell Black, M.A. · 1910
Black's Law Dictionary
A custom prevalent in some parts of England (also at some places on the continent) by which an estate descended to the youngest son in preference to his older brothers; the same as "Borough-English." As to junior "Barrister," "Counsel," "Creditor," "Execution," "Judgment," and "Writ," see those titles.