QUOTE(IrishSalesian @ Jun 14 2008, 10:38 AM)

I think it is the same difference between a diocese, and an archdiocese. One is the Metropolitan See of a few different dioceses and abbeys.
Great question hopefully this answers it: An Abbey," "monastery" and "priory" are roughly synonymous terms. A monastery generally refers to the building where the monks live. An abbey is a monastery governed by an abbot, while a priory is a monastery ruled by a prior under the auspices of the abbot of the mother abbey.
Here is a great article about our founder and how we were given the title Archabbey:Saint Vincent was founded by Archabbot Boniface Wimmer, O.S.B., when he emigrated from Bavaria in 1846. He and 18 companions laid the foundation for the first of many Benedictine schools and monasteries in the United States. A look at the life of this remarkable man provides a glimpse into the work of Divine Providence in preparing Archabbot Wimmer for his historic mission that continues to bear fruit today.
On January 14, 1809, Sebastian Wimmer was born in Thalmassing, Bavaria to Catholic parents in a time of cultural change and upheaval. Bavaria was changing under Napoleonic influence and the rationalists were in power. Monasteries and churches were suppressed until a new king, Ludwig I, came to power. He understood that “Bavarian” and “Catholic” could not be separated. He devised a strategy to re-integrate and re-invigorate the Catholic faith into Bavarian culture through academics and prayer. Immediately he established the Ludwig Maximillian University with its own Catholic Theology “think tank” called the Round Table, and he began re-establishing monasteries, the first of which was Saint Michael’s Abbey in Metten.
Father Sebastian Wimmer, a newly ordained priest, was invited by his bishop to enter the recently opened Saint Michael’s Abbey. He professed his solemn vows in 1833, taking the religious name, Boniface, in honor of the Benedictine saint who converted Germany centuries earlier. In his early monastic years, Father Boniface worked in the university, gymnasium and in various parishes and shrines near the abbey.
The mid-1800s witnessed a massive European immigration to the United States. Right after the Irish blazed a path, there soon followed a great wave of Germans. Father Boniface heard of the plight of German-speaking Catholics in the United States and wanted to help. His first plan was to establish a monastery and seminary in Bavaria to send German-speaking priests to minister to these people. However, his abbot declined to let him proceed, and this setback gave Father Boniface the ability to conceive a better idea -- to begin a monastery and school in America. At first his abbot would not permit it, but eventually, Father Boniface’s persistence paid off. He came to Pennsylvania with 14 lay brother candidates and 4 priesthood candidates. They began monastic life at Saint Vincent on October 24, 1846 and the first day of school was October 25, 1846.

These good monks wasted no time. In five years, there were 100 monks in the community, and in ten years, 200 monks. By 1855 Saint Vincent became an abbey, with Boniface Wimmer as its first abbot. The school grew quickly to include elementary, secondary, college, graduate and seminary curricula. Students were predominantly German-speaking at first, but soon there was a fine mix of many ethnicities and languages spoken on campus.
Boniface Wimmer was named Archabbot in 1883, in recognition of his many accomplishments. During his years in the United States he founded 152 parishes, five abbeys, and many schools. His application of Saint Benedict’s motto of "work and prayer" formed a model for successful monastic life in the United States. His blueprint for success was simple: First, establish a monastic community with strong monks who own the land they build upon. Second, establish a parish,. And lastly, establish a school. History proved him correct. Any foundation that was missing one or more of these factors did not succeed.
Archabbot Boniface died on the Solemnity of the Immaculate Conception, December 8, 1887, after forty-one years of leading the Benedictines in America. Sadlier’s Catholic Dictionary called him the greatest missionary in the 19th century in their 1888 publication.
So, therefore, since we are the first abbey and motherhouse of all the Abbey's within the American Cassinese Congregation, which was founded by Wimmer as well, we were granted the title Archabbey by the Holy Father.
Br. Gabriel Myriam, OSB
SVAmonks