A prelate is a member of the clergy having a special canonical jurisdiction over a territory or a group of people; usually, a prelate is a bishop. Prelate sometimes refers to the clergy of a state church with a formal hierarchy, and suggests that the prelate enjoys legal privileges and power as a result of clerical status. The word derives from Latin prælatus, the past participle of præferre, "to prefer;" it suggests that the prelate has been raised to his dignity by the act of a superior hierarch.
A prelature is the office of a prelate or the entire or the entire juridical entity composed of prelate, clergy and laity. Prelacy is the body of prelates as a whole, or a system of government, administration, or ministry by prelates.
An Honorary prelate does not excercise prelatial authority, but posesses the dignity and priviliges, such as form of address, dress, and formerly the right to pontificate under certain circumstances. In the United States, honorary prelates of the Roman Catholic Church are addressed as Monsignor.
In the Roman Catholic Church, the power to create Personal Prelatures was introduced in the 1983 Code of Canon Law; they are institutions having clergy and (possibly) lay members which would carry out specific pastoral activities. The adjective personal refers to the fact that, in contrast with previous canonical use for ecclesiastical institutions, the jurisdiction of the Prelate is not linked to a territory but over persons wherever they be.
The prelate, who may be a bishop, is appointed by the Pope, and governs the prelature with power of governance or jurisdiction in specific matters that pertain to the mission of the prelature.
The Church has the power of self-organization to pursue her mission. Exercising this power, the Church has established personal prelatures within her hierarchical structure, with the special feature that the faithful of the prelature continue to belong to their local church and to the diocese where they live. They continue to be under the full jurisdiction of their bishops.
For these and other reasons, personal prelatures are clearly different from religious institutes and the consecrated life in general, as well as from associations and movements of the faithful.
The first (and as of 2004, only) Personal Prelature is Opus Dei, erected by Pope John Paul II in 1982. In the case of Opus Dei, the clergy and the laity (both men and women) are organically united under the jurisdiction of the Prelate.