roll

1. Origins, structure, and basic meaning

• Structure: The on reading is てん, and the kun readings are ころがる, ころげる, ころがす, and ころぶ. It has 11 strokes and relates to rolling, falling, or rotating.
• Basic usage: 転ぶ is read ころぶ, and 回転 is read かいてん.

2. Common pitfalls and similar expressions

• 転ぶ / 回転
  • 転ぶ means to fall and is read ころぶ. It describes a person losing balance and falling.
  • 濡れた床で滑って転んだ。 means “I slipped and fell on the wet floor.”
  • 回転 means rotation or revolution and is read かいてん. It refers to rotation around an axis or to a counted number of rotations.
  • 取っ手を回すと歯車が回転する。 means “Turning the handle makes the gear rotate.”