1a. An administrative officer in charge of a college, faculty, or division in a university. b. An officer of a college or high school who counsels students and supervises the enforcement of rules. 2.Ecclesiastical The head of the chapter of canons governing a cathedral or collegiate church. 3.Roman Catholic Church A priest appointed to oversee a group of parishes within a diocese. 4. The senior member of a body or group: the dean of the Washington diplomatic corps.
ETYMOLOGY:
Middle English deen, from Old French deien, from Late Latin decnus, chief of ten, from decem, ten, or from Greek deknos, chief of ten (from deka, ten). See dek in Appendix I.