denudation; ablation
Geology term for the wearing away of the earth's surface by natural processes such as erosion and weathering.
The landscape changes due to denudation.
scraping; wearing down
General physical sense of scraping or wearing something down by friction or abrasion; less common than the geological use.
Use lubricant to prevent scraping of machine parts.
Compound of 削 (saku, 'scrape, shave') and 摩 (ma, 'rub, wear down'). The exact historical derivation is uncertain; the spelling is conventionally associated with the meaning of wearing away or denudation.