Pontifex Maximus was a spiritual title long before the Popes. It was the chief priest of Rome as far back as 200 BC.
There also of course the New Testament quotation:
According to BibleGateway.com the Greek word that is used is: καισαρος Is that the direct translation of Caesar ?
The “Caesar” in question though is Tiberius so would have been a descendant (at least by adoption, via Augustus) of Julius Caesar, and part of the Julio-Claudian dynasty.
Non Plus Ultra was, according to Greek mythology, written on the Pillars of Hercules (Gibraltar) as a warning. It means ‘nothing further beyond’.
Obviously the words ‘plus’ and ‘ultra’ have a different meaning in modern English.
Just like any number of other words.
Transliterated from the greek alphabet to latin alphabet it is KAISAROS.
Nothing to add, except to share the trivia that in classic Latin, “caesar” was pronounced the same way we pronounce “kaiser”.
And “v"s were pronounced like “w”'s, so when Julius Caesar said 'I came, I saw, I conquered” it sounded like Wenny, Widdy, Winky.
Jesus had asked “Whose face is on this coin?” and so he was probably using it as a proper name. Worked either way though. It was probably one of his most controversial statements when you consider the context of the times (Roman occupied Israelites being told “give the Romans what they ask for”).
Today he could ask about a dollar bill and say “Give to Washington what is Washington’s” and it would work, Washington now being synonymous with seat of government.
He was just ragging on his opponents - calling them “Weeny, Weedy, Weaky” 
I always assumed Caesar was referring to his enforcer, Vincenzo Vittorio DaVicci, aka “Vinnie the Clam”, “Vito the Hook”, and, on his business card, “Vinnie V. DaVicci, Dry Cleaning Equipment Wholesaler, Astoria”.
gesundheit!
(You knew that was coming)
Quoth Simplicio:
My understanding that the title of Imperator under the Republic was not formally granted, but was given to a military leader by informal popular consensus of the troops under his command. If you won lots of battles, kept the pay coming, and were otherwise good to your men, they’d respect you by calling you “imperator”.
Quoth Sampiro:
You know why it’s so hard to get a letter to Washington?
Because he died in 1799.
In Spain we usually say only Emperador - the “de Roma” is given by the context. It would be very strange to refer to Nero or Constantine as “el césar”. Augustus is the only one whom I remember hearing as César Augusto, and it’s mostly in the context of explaining his relationship with the town of Saragossa (Caesaraugusta).
Yes. As a commander, you typically needed your troops to acclaim you as imperator in order to be eligible for a triumph. By the end of the Republic, this could occasionally be done by bribery alone.
And possibly Shah.
Nope. Shah preceded Caesar ( Julius Caesar ) by several centuries. At least - we know it was used by the Achaemenids, but it is not outside the realm of possibility that they didn’t invent the word.
I’d say the same thing for French: the Roman Emperor is called “empereur” or “empereur romain” if more precision is needed; never “César” which is only used to refer to the family name.
Thanks, ignorance fought!