noun
A solemn, often romantic or lifelong promise. Common in literary and formal contexts.
二人は永遠の愛の契りを交わした。
The two exchanged a vow of eternal love.
Euphemistic and literary; used to refer to intimate relations in a poetic or indirect way.
契りを結ぶ夜、月が美しかった。
The night they consummated their bond, the moon was beautiful.
noun
Rare, archaic sense implying a fated connection, often between lovers. Modern Japanese uses 運命 or 宿命 instead.
古い物語では、契りが二人を結びつけると信じられていた。
In old tales, it was believed that destiny bound the two together.
約束 is a general, everyday promise, while 契り is a solemn, often romantic or lifelong vow.
誓い is a formal oath or vow, often public or legal, whereas 契り carries a more poetic, personal, and sometimes physical connotation.
Derived from the verb 契る (ちぎる, 'to pledge, to vow'). The noun form 契り nominalizes the action, carrying the sense of a binding promise or fated connection.