(pĕn'tӘkôst) [Gr.,=fiftieth], important Jewish and Christian feast. The Jewish feast of Pentecost, in Hebrew Shavuot, the Feast of Weeks, one of the three pilgrimage festivals, arose as the celebration of the closing of the spring grain harvest, which began formally in Passover 50 days prior; there are numerous references to it in the Bible. From Rabbinic times, the festival commemorates the giving of the law to Moses at Mt. Sinai.
On the Pentecost after the resurrection of Jesus (50 days from the Passover in which He was crucified), the Holy Spirit, according to the Acts of the Apostles, descended on the disciples in the form of tongues of fire accompanied by the sound of a rush of wind, and gave them the power of speaking in such a way that people of different languages could understand them. The Christian feast of Pentecost is an annual commemoration of this event, and it is solemnly observed as the birthday of the church and the feast of the Holy Spirit.
In ecclesiastical calendars Pentecost is the seventh Sunday after Easter and closes Eastertide. In the Western Church there are special observances, e.g., a penitential vigil, and in ancient times neophytes were baptized at this time. From the white garments of these converts comes Whitsunday, an English name for Pentecost. The great liturgical Latin hymns Veni Creator Spiritus and Veni Sancte Spiritus were composed for Pentecost. The Sunday after Pentecost is Trinity Sunday; until Advent the weeks are counted from Pentecost or Trinity.