grate (n.) Look up grate at Dictionary.com
late 14c., "grill for cooking;" early 15c., "iron bars or cagework across a door or window," from Anglo-Latin (mid-14c.), from Old French grate or directly from Medieval Latin grata "a grating, lattice," from Latin cratis "wickerwork, hurdle" (see hurdle (n.)). As a verb meaning "to fit with a grate," from mid-15c. Related: Grated; grating.
grate (v.) Look up grate at Dictionary.com
"to scrape, rub," late 14c. (implied in grated), from Old French grater "to scrape, scratch (out or off); erase; destroy, pull down" (Modern French gratter), from Frankish *kratton, from Proto-Germanic *krattojan (cognates: Old High German krazzon "to scratch, scrape," German kratzen "to scratch," Swedish kratta, Danish kratte "to rake, scrape"), probably of imitative origin. Senses of "sound harshly," and "annoy" are mid-16c. Italian grattare also is from Germanic. Related: Grated; grating.