夕日

1. Origins, structure, and basic meaning

• Structure: 夕日 (reading ゆうひ) is a noun for the evening or setting sun itself and for the reddish light it casts.
• Basic usage: It appears when the sun sinks behind a mountain or its light streams through a west-facing window.

2. Common pitfalls and similar expressions

• Sun and sunlight
  • In 夕日が沈む, the sun itself sets; in 夕日が差し込む, attention is on the light entering a space.
• Contrast with 夕焼け
  • 夕焼け is the reddening of the evening sky, while 夕日 directly names the setting sun or its light.