Tonsure

Definition:

(n.) The act of clipping the hair, or of shaving the crown of the head; also, the state of being shorn.
(n.) The first ceremony used for devoting a person to the service of God and the church; the first degree of the clericate, given by a bishop, abbot, or cardinal priest, consisting in cutting off the hair from a circular space at the back of the head, with prayers and benedictions; hence, entrance or admission into minor orders.
(n.) The shaven corona, or crown, which priests wear as a mark of their order and of their rank.

Compare tonsure with other words:

tonsure vs. tonsured