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1. Origins, structure, and basic meaning

• Structure: 摩 has 15 strokes and the on-reading ま. 摩擦 (まさつ) means friction; 摩耗 (まもう) means wear.
• Basic usage: 摩擦 covers physical friction and conflict between people or groups. 摩耗 concerns shoe soles or parts wearing down.

2. Common pitfalls and similar expressions

• Friction and wear
  • 靴底と地面の摩擦 means friction between shoe soles and the ground. 部署に摩擦が生じた means conflict arose between departments.
  • 靴底は摩耗し says that the soles wore down. Distinguish friction expressed by 摩擦 from the worn condition resulting from use expressed by 摩耗.