Tonsure
2 of the 6 encyclopedias on this shelf carry an entry for Tonsure. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
in ecclesiology and Church history, the shaving of the crown in a circle, which is a distinguishing mark of clerks in the Roman Church. Most of the mendicant and cloistered orders allow only a narrow strip of hair to grow round the head, all above and below being shaved; the tonsure of secular clerics is small. The tonsure is a necessary preliminary to entering the clerical state, whether secular or religious; in the former case it is conferred by the bishop of the diocese, in the latter by the head of the religious house, if a mitered abbot. It invests the receiver with all the privileges of a cleric, and furnishes a means to distinguish the higher from the lower clergy, as the extent of the tonsure increases with the rank till the priesthood is reached. Also, the act of admission to the clerical state. At first it was never given without some minor order being conferred at the same time, but this practice ceased in the 7th century.
Aiton's Encyclopedia (1910)
ton'shur, a shaven place on the head of a priest. The Roman Catholic tonsure or the tonsure of St. Peter consists of a bare circle on the top of the head. The first removal of the hair is performed by a bishop or cardinal and is one of the solemn rites of consecration to the priesthood. The candidate is pledged to shave the top of his head once a month. The higher the rank of a Catholic the wider may be his tonsure. The tonsure of the Greek Church , or the tonsure of St. Paul, consists in shaving, or at least clipping closely, the entire head. A third tonsure, the Celtic, or tonsure of St. John, consists in the removal of the hair in front of a line drawn over the top of the head from ear to ear.
What Has Changed in the Last Century
When Collier's wrote in 1921 that "the tonsure is a necessary preliminary to entering the clerical state," it was stating Roman Catholic law as it then stood. That law was swept away by Paul VI's motu proprio Ministeria quaedam of 1972, which abolished the rite of first tonsure along with the minor orders and the subdiaconate; a man now becomes a cleric by ordination as a deacon, and the shaven crown has vanished from ordinary Catholic practice. It survives among traditionalist societies and in some religious orders, and Eastern Orthodox monks are still "tonsured" at profession, though there the hair is cut symbolically rather than the whole head shaved as Aiton's 1910 account describes. The Celtic tonsure of Aiton's third type had already been extinct for a thousand years when he wrote, a casualty of the Easter controversies of the seventh century.
Written for this edition, 2026.