Prelature (territorial or personal)
Assigning a territory or a group to a prelature removes it from the normal Church hierarchy and places it directly under the pope. This is done when, for various reasons, the Vatican does not wish to submit it to the jurisdiction or the oversight of a bishop.
(Latin: praelatura nullius, from nullius “none”, i.e., under no diocese)
A prelature is placed directly under the pope, rather than under a bishop, as is usual in the Church hierarchy. A territorial prelature can be used in a concordat to tactfully wait out a jurisdictional dispute: the territory in question is withdrawn from contention until episcopal tempers have cooled. A personal prelature, on the other hand, applies to a group, rather than a territory, this category was established in order to carve a niche outside the oversight of a bishop for Opus dei. This is the first and only personal prelature. One personal prelature is Opus dei. Another one is the Legion of Christ. (See: How secrecy shielded the Legion of Christ from the law.)
E.g., Apostolic administration of Burgenland, in Austria was elevated to Personal prelature when the Hungarian prelates vigorously opposed the loss of "their" church territory after the national borders changed following WWI. Burgenland was placed directly under the pope for an indefinite period, until the Hungarian Church could be brought to accept post-war reality. (Austrian concordat 1933 Art.4.2)