also: えんゆう
noun
Refers to a link or tie between people, events, or things, often implying a causal or circumstantial bond.
この事件には何か縁由があるに違いない。
There must be some connection behind this incident.
noun
Indicates the underlying cause, source, or motivation for an event or action. Sense 3 (motive) is a specific application of this broader meaning.
彼が辞職した縁由は明らかではない。
The reason for his resignation is not clear.
犯行の縁由を調べる。
Investigate the motive behind the crime.
Compound of 縁 (en, 'connection, fate') and 由 (yu, 'reason, origin'). The exact historical derivation is uncertain, but the combination conveys the idea of a causal link or background.