Old English grindan "to rub together, grate, scrape," forgrindan "destroy by crushing" (class III strong verb; past tense grand, past participle grunden), from Proto-Germanic *grindanan (cf. Dutch grenden), related to ground, from PIE *ghrendh- "to grind" (cf. Latin frendere "to gnash the teeth," Greek khondros "corn, grain," Lithuanian grendu "to scrape, scratch"). Meaning "to make smooth or sharp by friction" is from c.1300. Most other Germanic languages use a verb cognate with Latin molere (cf. Dutch malen, Old Norse mala, German mahlen).