Which word describes the action of wearing down or rubbing away through friction?

The term that precisely describes the action of wearing down or rubbing away through friction is "abrade." This word specifically refers to the process of scraping or wearing off a material's surface due to frictional interaction. In contexts such as geology, manufacturing, or materials science, "abrade" accurately captures the essence of this action, indicating a gradual removal of material through mechanical action.

While "scrape" might suggest a similar action of rubbing something off a surface, it does not encompass the broader idea of continuous wear that occurs over time. "Grind" typically refers to a more forceful or abrasive action involving reduction of size or creation of fine particles, often associated with tools or machines. "Polish," on the other hand, is associated with making a surface smooth and shiny, rather than wearing it down. Thus, "abrade" stands out as the most fitting term for describing the specific action of wearing down due to friction.