Your Answer is: Senatus Populusque Romanus
Step-by-step explanation:
Upon the triumphal arches, the altars, and the coins of Rome, SPQR stood for Senatus Populusque Romanus (the Senate and the Roman people). In antiquity, it was a shorthand means of signifying the entirety of the Roman state by referencing its two component parts: Rome's Senate and her people.