wikipedia

Tonsure (/ˈtɒnʃər/) is the practice of cutting or shaving some or all of the hair on the scalp as a sign of religious devotion or humility. The term originates from the Latin word tonsura (meaning "clipping" or "shearing") and referred to a specific practice in medieval Catholicism, abandoned by papal order in 1972. Tonsure, in its earliest Greek and Roman origin, was used as a sign or signifier for slavery. Tonsure can also refer to the secular practice of shaving all or part of the scalp to show support or sympathy, or to designate mourning. Current usage more generally refers to cutting or shaving for monks, devotees, or mystics of any religion as a symbol of their renunciation of worldly fashion and esteem.