www.jewishvirtuallibrary.org/jsource/Judaism/holidayc.html
Read your own posting. The idea of the Holy Spirit descending on the Apostles in the upper room is heresy and blasphemy to Jews. The only connection is that Christians built upon the idea of Shavuot to the Christian definition of Pentecost in the same manner that Christians built upon the idea of Passover to the Christian definition of the Eucharist.
To say that the Christian definition of Pentecost is the same as the Jewish one, not only goes against the Jewish Library, but it also is equivalent to the LDS version of God the Father, the Son and the Holy Spirit being exactly the same as the Christian one, which of course it is not.
Remember now? Who disappeared? Hmm? I don't hear you..
It is God that gives eyes to see and ears to hear. Perhaps you missed that appointment.
They were not in Jerusalem to celebrate a Christian or Jewish Pentecost. The only “Pentecost” celebration going on was the Shavouts, a.k.a., Pentecost. (See above)
The only “Christian definition of Pentecost” is that found in the Bible and that has, in several posts to you, been explained.
If some celebrate the outpouring of spirit upon Christians at the same time Jewish Shavouts, a.k.a., Pentecost was taking place that is another matter and what Jews think of that outpouring of spirit is irrelevant.
As is the rest of your post.
So do try to pay attention as I've no more time to waste explaining the obvious to you.