shadow

1. Origins, structure, and basic meaning

• Structure: 影 has 15 strokes, the on-reading えい, and the kun-reading かげ. 影 (かげ) means a shadow, while 影響 (えいきょう) means an influence or effect.
• Basic usage: 影 names a shadow created by light; 影響 concerns the effect one factor has on something else.

2. Common pitfalls and similar expressions

• A shadow and an effect
  • 木の影が長く伸びた means that the tree's shadow stretched out. It describes the shape of a shadow in the setting sun.
  • 集中力に影響する means to affect concentration. 風の影響で扉が何度も揺れた describes a door shaking several times because of the wind.