Aisneesse
A New Law Dictionary and Glossary · Alexander M. Burrill · 1850
A New Law Dictionary and Glossary
Aisnesse.
L. Fr. jX. Lat. aesnecia, q. v.] The right or privilege of the eldest, or first bora; esnecy, (q. v.) Spelman, voc.
Aesnecia
Kelham gives ainneesche as another form.