discus (n.)

circular piece of stone or metal plate about 12 inches in diameter, pitched from a fixed spot the greatest possible distance as a gymnastic exercise and an athletic contest, 1650s, from Latin discus "discus, disk," from Greek diskos "disk, quoit, platter," related to dikein "to throw," which is perhaps from PIE *dik-skos-, from root *deik- "to show, pronounce solemnly; also in derivatives referring to the directing of words or objects" [Watkins]; but Beekes says dikein is of Pre-Greek origin. The notion is "to throw" as "to direct an object."