"hulled grain coarsely ground or crushed; oatmeal," early 14c., from grot "piece, fragment," from Old English grot "particle," from same root as grit. The word also meant "excrement in pellets" (mid-15c.).
medieval European coin, late 14c., probably from Middle Dutch groot, elliptical use of adj. meaning "great, big" (in sense of "thick"); see great. Recognized from 13c. in various nations, in 14c. it was roughly one-eighth an ounce of silver; the English groat coined 1351-2 was worth four pence. Also cf. groschen.