Medical and general term for a superficial skin injury caused by rubbing or scraping.
I fell and got an abrasion on my knee.
An abrasion is a minor injury, but it needs disinfection.
Compound of 擦 (satsu, 'rub, scrape') and 傷 (shō, 'wound, injury'). The reading さっしょう results from the assimilation of さつ + しょう.