HITSUNDAY, a solemn festival of the Christian church, observed on the fiftieth day after Easter, in memory of the descent of the Holy Ghost upon the apostles in a visible appearance of fiery cloven tongues, and of the miraculous powers which were then conferred upon them. It is called Whitsunday, or White Sunday, because it being one of the stated times for baptism in the ancient church, those who were baptized put on white garments, as types of that spiritual purity which they received in baptism. At the descent of the Holy Ghost upon the apostles happened upon the day which the Jews called Pentecost, this festival retained the name of Pentecost among the Christians.