Emily Dickinson Lexicon

DEAN, n. [Fr. doyen, the eldest of a corporation; Arm. dean; Sp. dean, decano; Port. deam, decano; It. decano; from L. decanus, the leader of a file ten deep, the head of a college, from decem, Gr. δεκα, W. deg, ten; so named because originally he was set over ten canons or prebendaries. – Ayliffe.]

1. In England, an ecclesiastical dignitary in cathedral and collegiate churches, and the head of a chapter; the second dignitary of a diocese. Ancient deans are elected by the chapter in virtue of a conge d'elire from the king and letters missive of recommendation; but in the chapters founded by Henry VIII, out of the spoils of dissolved monasteries, the deanery is donative, and the installation merely by the king's letters patent. – Encyc.
2. An officer in each college of the universities in England. – Warton.
3. In the United States, a registrar in a medical school. Rural dean, or arch-presbyter, had originally jurisdiction over ten churches; but afterward he became only the bishop's substitute, to grant letters of administration, probate of wills, &c. His office is now lost in that of the archdeacon and chancellor. – Encyc. Dean of a monastery, a superior established under the abbot, to ease him in taking care of ten monks. Hence his name. – Encyc. Dean and Chapter, are the bishop's council, to aid him with their advice in affairs of religion, and in the temporal concerns of his see. – Encyc.