rock: English has two words rock, both of uncertain origin. The older, ‘sway’ [11], goes back to a prehistoric Germanic base *rukk- ‘move’, which also produced German rücken ‘move’ and Dutch rukken ‘pull, jerk’, but beyond that its trail goes cold. Rock ‘stone’ [14] was borrowed from Old French rocque. This has relatives in Italian rocca and Spanish roca, but where it ultimately came from is not known. The French word is also the ultimate source of English rococo. => rococo
