The Pope is also known as the Pontiff: from where does the title "Pontiff" come?

The modern word Pontiff is not an old dialect word or a modern dialect word. It comes from the words "pontifex maximus", Latin for "the greatest bridge builder". The title Pontifex Maximus was applied to the high priest of the College of Pontiffs (Collegium Pontificum) in ancient Rome (before the arrival of Christianity), Some time after the Roman republic ceased to be this title was then later transferred to the bishop of Rome; it was never applied to the bishop of Jerusalem.