Pentecost \Pen"te*cost\, n. [L. pentecoste, Gr. ? (sc. ?) the fiftieth day, Pentecost, fr. ? fiftieth, fr. ? fifty, fr. ? five. See Five, and cf. Pingster.]

1. A solemn festival of the Jews; -- so called because celebrated on the fiftieth day (seven weeks) after the second day of the Passover (which fell on the sixteenth of the Jewish month Nisan); -- hence called, also, the Feast of Weeks. At this festival an offering of the first fruits of the harvest was made. By the Jews it was generally regarded as commemorative of the gift of the law on the fiftieth day after the departure from Egypt. [1913 Webster]

2. A festival of the Roman Catholic and other churches in commemoration of the descent of the Holy Spirit on the apostles; which occurred on the day of Pentecost; -- called also Whitsunday. --Shak. [1913 Webster]

Source: The Collaborative International Dictionary of English v.0.48
 

Whitsunday \Whit"sun*day\, n. [White + Sunday.]

1. (Eccl.) The seventh Sunday, and the fiftieth day, after Easter; a festival of the church in commemoration of the descent of the Holy Spirit on the day of Pentecost; Pentecost; -- so called, it is said, because, in the primitive church, those who had been newly baptized appeared at church between Easter and Pentecost in white garments. [1913 Webster]

2. (Scots Law) See the Note under Term, n., 12. [1913 Webster]

Source: The Collaborative International Dictionary of English v.0.48
 

Whitsunday

Source: WordNet (r) 2.0
 

Whitsunday \Whit"sun*day\, n. [White + Sunday.]

1. (Eccl.) The seventh Sunday, and the fiftieth day, after Easter; a festival of the church in commemoration of the descent of the Holy Spirit on the day of Pentecost; Pentecost; -- so called, it is said, because, in the primitive church, those who had been newly baptized appeared at church between Easter and Pentecost in white garments.

2. (Scots Law) See the Note under Term, n., 12.

Source: Webster's Revised Unabridged Dictionary (1913)
 

Pentecost \Pen"te*cost\, n. [L. pentecoste, Gr. ? (sc. ?) the fiftieth day, Pentecost, fr. ? fiftieth, fr. ? fifty, fr. ? five. See Five, and cf. Pingster.]

1. A solemn festival of the Jews; -- so called because celebrated on the fiftieth day (seven weeks) after the second day of the Passover (which fell on the sixteenth of the Jewish month Nisan); -- hence called, also, the Feast of Weeks. At this festival an offering of the first fruits of the harvest was made. By the Jews it was generally regarded as commemorative of the gift of the law on the fiftieth day after the departure from Egypt.

2. A festival of the Roman Catholic and other churches in commemoration of the descent of the Holy Spirit on the apostles; which occurred on the day of Pentecost; -- called also Whitsunday. --Shak.

Source: Webster's Revised Unabridged Dictionary (1913)