Descent of the Holy Spirit

Pentecost
Mosaic representing Pentecost in the Cathedral Basilica of Saint Louis
Also called	Whitsunday
Observed by	Roman Catholics, Eastern Catholics, Old Catholics, Protestants, Eastern Orthodox, Oriental Orthodox, Anglicans and other Christians
Type	Christian
Significance	Celebrates the descent of the Holy Spirit upon the Apostles and other followers of Jesus
Celebrations	Religious (church) services, festive meals, processions, baptism, confirmation, ordination, folk customs, dancing, spring & woodland rites, festive clothing
Observances	Prayer, vigils, fasting (pre-festival), novenas, retreats, Holy Communion, litany
Date	Easter + 49 days
2017 date	June 4 (Western Churches) June 4 (Eastern Churches)
2018 date	May 20 (Western Churches) May 27 (Eastern Churches)
2019 date	June 9 (Western Churches) June 16 (Eastern Churches)
2020 date	May 31 (Western Churches) June 7 (Eastern Churches)
Related to	Shavuot

The Christian feast day of Pentecost is seven weeks after Easter Sunday: that is to say, the fiftieth day after Easter inclusive of Easter Sunday. It commemorates the descent of the Holy Spirit upon the Apostles and other followers of Jesus Christ while they were in Jerusalem celebrating the Feast of Weeks, as described in the Acts of the Apostles. Some Christians believe that this event represents the birth of the Church. The Feast of the Ascension occurs 40 days after Easter, so Pentecost is a moveable feast. In Eastern Christianity, Pentecost can also refer to the entire 50 days of Passover, and the book containing the liturgical texts for Paschaltide is called the Pentecostarion.

The holy day is also called "White Sunday" or "Whitsunday", especially in the United Kingdom where Whit Monday was also a public holiday (now fixed by statute on the last Monday in May). The Monday after Pentecost is a legal holiday in many European nations.

The term Pentecost comes from the Greek Πεντηκοστή (Pentēkostē) meaning "fiftieth" (50th). It refers to the festival celebrated on the fiftieth day after Passover, also known as the "Feast of Weeks" and the "Feast of 50 days" in rabbinic tradition.

The Septuagint uses the term Pentēkostē to refer to the "Feast of Pentecost" only twice, in the deuterocanonical Book of Tobit and 2 Maccabees. The Septuagint writers also used the word in two other senses: to signify the year of Jubilee (), an event which occurs every 50th year, and in several passages of chronology as an ordinal number. The term has also been used in the literature of Hellenistic Judaism by Philo of Alexandria and Josephus.