What is the Meaning of the Word “Pope”?

In the language of the ancient Greeks the word Pope means father - but more in a child’s term of endearment sort of way, which would actually make it more equivalent to the word daddy.The Latin language later adapted the term as a sort of honorary title. Both eastern and western Christians began applying the term to heads of church, priests and bishops alike. Over time, Latin-based Christians began gradually limiting their use of the title. This did not happen within the Eastern Orthodox Church - priests are still called Pope in Greece, Russia and Serbia. At the start of the 5th century, the title Pope was beginning to be applied primarily to the bishop of Rome. By the 8th century, it was nearly exclusively applied to the bishop of Rome.

References:

Chronicle of the Popes by P.G. Maxwell-Stuart