Bigne
A Dictionary of Law · Henry Campbell Black · 1891
A Dictionary of Law
Fr. Eldest; eldest-born. The term is of common occurrence in the old books. Thus, bastard eigne means an illegitimate son whose parents afterwards marry and have a second son for lawful issue, the latter being called mulier puisne, (after-born.) Eigne is probably a corrupt form of the French "ainé."
2 Bl. Comm. 248; Litt. § 399.