Answer:
peace
Step-by-step explanation:
"Pax" is latin for "peace". "Pax Romana" in addition to describe the specific time period of peace, became an expression on its own meaning "long peace".
However, if there was peace within the Roman territories during that period, Romans were still fighting enemies in the periphery of the territories, to protect the empire against invasions and other war effects. But they didn't seek the expansion of the territories.