n 1: erosion by friction [syn: abrasion, corrasion, detrition]
2: the wearing down of rock particles by friction due to water
or wind or ice [syn: grinding, abrasion, detrition]
3: sorrow for sin arising from fear of damnation [syn: contrition, contriteness]
4: a wearing down to weaken or destroy; "a war of attrition"
5: the act of rubbing together; wearing something down by