Whitsunday is commonly known as the Christian holiday Pentecost, which celebrates the descent of the Holy Spirit on the disciples of Jesus. However, there are other synonyms that can be used for the term Whitsunday, including Pentecost Sunday, Whit Sunday, and even Pinkster. In some regions of the world, Whitsunday is also referred to as the Feast of the Fiftieth Day or simply as Holy Spirit Day. Regardless of the name used to refer to this important Christian holiday, it holds significance as it marks the beginning of the church's mission to spread the good news of Jesus Christ.