Quirinus was the name under which Romulus was worshipped after he became a god, or else that of an early Roman war god resembling Mars. He may have originated as a Sabine god from the town of Cures, and get his name from there, and some authorities say that the Latin word Quiris, which came to mean 'citizen', also came from this town.

After the union of the Sabines and the Romans, the latter called themselves (as civilians) Quirites. On specially solemn occasions they were called Populus Romanus Çhiirites, 'the Roman people, citizens'. William Smith reminds us that it was a reproach for soldiers to be called Quirites instead of milites.

Other sources maintain that the name of Quirinus is connected with quirts or curis, 'spear', which was originally a Sabine word. Quirinus was certainly often represented with a spear. A third theory is that his name was originally something like covirium, 'assembly of men'.