1.
reason, basis, grounds
The fundamental reason or basis for something. A somewhat literary word used in the pattern 「...の所以」 to express why something is so. Often used to explain the essential nature or defining characteristic of something.
それが彼の強さの所以だ。
That is the basis of his strength.
人間が人間たる所以は何か。
What is it that makes humans human?
この地域が名産地と呼ばれる所以は、独特の気候と土壌にある。
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」 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」 (what makes X truly X), which sounds elevated and philosophical.
COMMON PATTERNS:
- ...の所以: the reason for..., the basis of...
- XがXたる所以: what makes X truly X
SIMILAR WORDS:
- 理由: reason (everyday, neutral)
- 根拠: grounds, basis (formal, factual)