一因(いちいん)

いちいん
noun
one cause, a contributing factor
formalacademicabstract
See also: 一員(いちいん) (one member)
1. one cause, a contributing factor
One of several causes or contributing factors. Implies that the cause mentioned is not the only one, but one among multiple factors.
ストレスも病気(びょうき)の一因(いちいん)だ。
Stress is also a contributing factor to illness.
人手(ひとで)不足(ぶそく)が事故(じこ)の一因(いちいん)となった。
A shortage of workers was one cause of the accident.
食生活(しょくせいかつ)の乱(みだ)れが生活習慣病(せいかつしゅうかんびょう)の一因(いちいん)になっていると言(い)われている。
Poor eating habits are said to be a contributing factor to lifestyle diseases.

Common patterns

  • ～の一因(いちいん)だ: is a contributing factor of ~
  • ～の一因(いちいん)となる: become a contributing factor of ~
  • ～の一因(いちいん)になっている: is one of the factors behind ~

Usage

Using 一因(いちいん) implies the speaker acknowledges multiple causes. It is more measured than 原因(げんいん) (cause), which can imply a single or primary cause.

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A somewhat formal word, common in news, academic writing, and analysis.

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Added 2026.2.9 11:36 · Revised 2026.10.11 3:20
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