What does Pentekoste mean?

"Pentekoste" is the Greek word for Whitsun/Pentecoste. On Pentecoste day the language miracle happened: Eventhough people spoke in their own mother tongues, they understood each other.

The language miracle
When the day of Pentecoste had come, they were all together in one place. And suddenly a sound came from heaven like the rush of a mighty wind, and it filled all the house where they were sitting.
And there appeared to them tongues as of fire, distributed and resting on each one of them. And they were all filled with the Holy Spirit and began to speak in other tongues, as the Spirit gave them utterance.
Now there were dwelling in Jerusalem Jews, devout men from every nation under heaven. And at this sound the multitude came together, and they were bewildered, because each one heard them speaking in his own language.
And they were amazed and wondered, saying," Are not all these who are speaking Galileans? And how is it that we hear, each of us in his own native language? Parthians, Medes and Elamites and residents of Mesopotamia, Judea and Cappadocia, Pontus and Asia, Phrygia and Pamphylia, Egypt and the parts of Libya belonging to Cyrene, and visitors from Rome, both Jews and proselytes, Cretans and Arabians, we hear them telling in our own tongues the mighty works of God."
And all were amazed and perplexed, saying to one another,"What does this mean?" But others mocking said,"They are filled with new wine."