marriage contract; engagement agreement
Refers to a formal agreement or arrangement to marry, often with a traditional or contractual nuance. Not an everyday word for engagement; 婚約 is more common.
A marriage contract was exchanged between the two families.
Compound of 縁 (en, 'bond, tie, relationship') and 定め (sadame, 'arrangement, decision'). The exact historical derivation is uncertain, but the term likely originated in the context of arranged marriages.