rub

1. Origins, structure, and basic meaning

• Structure: 擦 has 17 strokes and the on-reading さつ. 擦る (こする) means to rub; 擦れる (すれる) means to rub against something or wear away.
• Basic usage: Distinguish actively rubbing hands or stains from shoes chafing against the body or printing wearing away.

2. Common pitfalls and similar expressions

• Different readings and forms
  • This word 擦る is read こする; 擦って is its て-form in the example about rubbing hands. Keep its initial reading distinct from すれる for 擦れる.
  • 足首に擦れて describes rubbing against the ankle. 文字が擦れて読めなくなった describes printing wearing away until it could no longer be read.