Easter
2 of the 7 encyclopedias on this shelf carry an entry for Easter. Both are reproduced below, so you can see where they agree and where they differ.
Aiton's Encyclopedia (1910)
es'ter, a festival celebrating the resurrection of Jesus Christ. By general agreement Easter Day fell on a Sunday; but for centuries, owing to changes in the calendars and other causes, there was confusion as to which Sunday should be thus observed. The rule adopted by the Roman Catholic church and by the Church of England is that Easter Day is the first Sunday following the Pascal full moon . This full moon is the one that occurs on or after March 21st. If the full moon occurs on Sunday, March 21st, Easter is the Sunday following, or March 28th. Even this ruling gives a wide range for the date of Easter. In case the full moon should occur on Saturday, March 21st, the following day, March 22d, would be Easter Sunday, the earliest date possible. In case a full moon should fall on Monday, March 20th, the Pascal, which is the first full moon after the 21st, would not occur until four weeks later, on April 17th, bringing Easter Sunday on April 23d. This is the latest date possible. In 1905 Easter fell on this date. Easter closes the forty days of Lent. Its solemnities are supposed to usher in gaiety in fashionable circles. The flower of the season is the beautiful white Easter lily. Florists have developed great skill in bringing this flower into full bloom at the right time. The habit of presenting Easter eggs to one's friends is a custom thought to have been derived from the Persian magi, the egg being the symbol of creation, birth, or resurrection,--possibly the re-creation of spring. Dying the eggs is a Christian addition; red, in particular, symbolizing the blood of the redemption.
Collier's New Encyclopedia (1921)
the appellation given, with some small variation in the several languages and dialects, by the nations of Teutonic descent, to the festival kept in commemoration of our Saviour's resurrection. The Latin nations called the same feast by words derived from Lat. Pascha; Gr. Pascha; and remotely from the Hebrew Pesachh, meaning the Passover, whence the French Pâque (O. Fr. Pask and Pasque); in Spanish, Pascua; in Port. Pascos; and in Italian Pasqua. From the same source, also, the word Pasche has been introduced into Anglo- Saxon. Thus no distinctively Christian name exists for the resurrection festival, one of the two being of ethnic and the other of Jewish origin.