Meaning

noun a long oar that is mounted at the stern of a boat and moved left and right to propel the boat forward

noun each of a pair of short oars that are used by a single oarsman

noun a racing shell that is propelled by sculls

originFrom Middle English sculle (“a type of oar”), of uncertain origin, possibly from North Germanic, from Old Norse skola (“to rinse, wash”).

Etymology from Wiktionary, CC BY-SA 3.0