紅葉

1. Origins, structure, and basic meaning

• Structure: 紅葉 (こうよう) means autumn foliage or the process of leaves changing color. The examples use nominal and verbal roles.
• Basic usage: Mountain foliage glows in the setting sun; trees begin changing color as temperature falls.

2. Common pitfalls and similar expressions

• Autumn foliage viewed as scenery and trees entering color change
  • 山の紅葉 is a noun for leaves or scenery, while 木々が紅葉し始める is a verbal expression for trees beginning to change color. Reading can vary by context.