The only time the Greek word
pascha (Passover) is used in the New Testament referring to a Post-Resurrection timeline is in Acts 12:4 where the King James Bible correctly has translated this Greek word as Easter.
In Greek, from which the King James New Testament was translated, Easter is the best translation for that particular Passover. Luke 22:1 and Ezekiel 45:21 both show that the entire feast of unleavened bread was called the Passover. The King James is accurate as it uses the word “Passover”
before the death and resurrection of Christ and then “Easter” the only time the word occurs in the book of Acts
after His resurrection.
There is an English / Anglo-Saxon usage of the word “Easter” pre-dating the King James (and Tyndale), and an etymological derivation from the German “Oster”. Until Tyndale, though, the English held in common with the European tongues (excepting German) the use of the transliterated
pascha for both the Jewish Passover and the post-resurrection celebration and its transformed Passover meal / Lord’s Supper. Tyndale differentiated between the two with linguistic brilliance, which was followed by the King James Bible.
For an enjoyable tour of the usage of this word – and the coining by Tyndale of the word “Passover” as well – see Nick Sayers’ article,
Why we should not Passover Easter. Sayers explains why it is theologically and Scripturally correct to differentiate between Passover and Easter, as has been done. And it is made clear that the German "Oster" has the meaning of resurrection in its usage.
You needn’t groan, Tim, when Gipp states as he does regarding these two words – and the Geneva Bible. It’s not a “mistranslation” as he says, but Tyndale’s – the King James Bible following – is a
better translation.
Sayers again (after the above links to Woodrow and Kinney) shows the error of Hislop’s asserting that Easter derives from Ishtar. This is an urban legend among Biblical scholars, which should be pretty well debunked by now – but evidently is not.