flood

1. Origins, structure, and basic meaning

• Structure: 洪 has 9 strokes and appears in the word for a flood.
• Basic usage: 洪水 is read こうずい.

2. Common pitfalls and similar expressions

• Whole-word reading
  • The final part of 洪水 is ずい; its reading is not formed by joining representative character readings unchanged.
• Actual damage and an assumed scenario
  • 昔の洪水で浸水した範囲 is the area inundated by a past flood.
  • 洪水を想定した避難訓練 is an evacuation drill based on a flood scenario. It does not mean a flood actually occurred during the drill.