Conventional
A New Law Dictionary and Glossary · Alexander M. Burrill · 1850
A New Law Dictionary and Glossary
[from Lat. conventio, q. v.] That which is produced by, or depends upon the agreement or mutual arrangement of parties. Conventional estates are those estates for life, which are expressly created by the act of the parties; as distinguished from legal estates, or those which are created by construction and operation of law.
2 Bl. Com. 120.