Strong’s Greek
G4005 — pentekoste
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
πεντηκοστή
pentekoste — pronounced pen-tay-kos-tay'
feminine of the ordinal of 4004; fiftieth (2250 being implied) from Passover, i.e. the festival of "Pentecost":--Pentecost. see GREEK for 4004 see GREEK for 2250
3 occurrences in the KJV.
Acts 2:1
And when the day of Pentecost was fully come, they were all with one accord in one place.
Acts 20:16
For Paul had determined to sail by Ephesus, because he would not spend the time in Asia: for he hasted, if it were possible for him, to be at Jerusalem the day of Pentecost.
1 Corinthians 16:8
But I will tarry at Ephesus until Pentecost.