noun
Refers to the underlying reason, cause, or meaning behind something. Often used in formal or written contexts, and in set phrases like 由ありげ or 由なく.
彼が辞職した由を聞かせてほしい。
Please tell me the reason he resigned.
この手紙には深い由があるらしい。
This letter seems to have a deep significance.
noun
I hear that; it is said that; reportedly
Only when written 由
Used to convey hearsay or reported information, often in the pattern ～との由 or ～の由. Restricted to the kanji 由. Formal and somewhat literary.
お元気でいらっしゃる由、何よりです。
I hear that you are doing well, which is wonderful.
会議は延期されたとの由。
I hear that the meeting has been postponed.
The kanji 由 originally depicted a sprout emerging from a field, symbolizing origin or source. The reading よし is a native Japanese word meaning 'reason' or 'way', and the kanji was assigned to it based on meaning.