所以(ゆえん)

ゆえん
noun
reason, grounds, basis
formalwrittenliterary
1. reason, basis, grounds
The fundamental reason or basis for something. A somewhat literary word used in the pattern 「...の所以(ゆえん)」 to express why something is so. Often used to explain the essential nature or defining characteristic of something.
それが彼(かれ)の強(つよ)さの所以(ゆえん)だ。
That is the basis of his strength.
人間(にんげん)が人間(にんげん)たる所以(ゆえん)は何(なに)か。
What is it that makes humans human?
この地域(ちいき)が名産地(めいさんち)と呼(よ)ばれる所以(ゆえん)は、独特(どくとく)の気候(きこう)と土壌(どじょう)にある。
The reason this region is called a famous production area lies in its unique climate and soil.

Usage

A literary/formal word. The most common pattern is 「Xの所以(ゆえん)」 meaning "the reason for X" or "what makes X what it is." Also used in the rhetorical pattern 「XがXたる所以(ゆえん)」 (what makes X truly X), which sounds elevated and philosophical.

Common patterns

  • ...の所以(ゆえん): the reason for..., the basis of...
  • XがXたる所以(ゆえん): what makes X truly X

Similar words

Related Words

Compare: 理由(りゆう) (reason)
Compare: 根拠(こんきょ) (grounds, basis)
general
Added 2026.2.22 21:00 · Revised 2026.9.2 13:01
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