From a compound of dia and a derivative of orthos, meaning to straighten thoroughly; rectification, i.e. (specially) the Messianic restauration -- reformation.
KJV: And when he was called forth, Tertullus began to accuse him, saying, Seeing that by thee we enjoy great quietness, and that very worthy deeds are done unto this nation by thy providence,
NASB: After Paul had been summoned, Tertullus began to accuse him, saying to the governor, "Since we have through you attained much peace, and since by your providence reforms are being carried out for this nation,