Some helpful vocabulary
A theological school is a graduate school of higher learning that offers theological education. Generally, graduates of theological schools become members of the clergy or lay leaders in their churches. Some become teachers of theology or its related disciplines (like history or Bible).
The most common standard degree offered by Protestant and Catholic theological schools in North America is the master of divinity (or M.Div.) degree. But theological schools also offer M.A. degrees, Ph.D. degrees, and many specialized master's degrees in subjects like music, counseling, and youth ministry. A few theological schools have undergraduate departments that offer bachelor's degrees in theological subjects.
Most theological schools are accredited by the Assocation of Theological Schools in the United States and Canada. Many are also accredited by one of the regional accrediting organizations. A few are accredited by other bodies like the Association for Biblical Higher Education. Some have chosen not to seek accreditation at all. Catholic schools, whether accredited or not, are governed by the Vatican's Congregation for Catholic Education.
Among Catholics, theological schools that train men for the priesthood are called called major seminaries or simply seminaries. Some (but not all) major seminaries have an undergraduate school, usually called a college seminary, and all have a graduate school known as a theologate. But a Catholic school that trains lay leaders (or members of consecrated religious orders) is usually called a school of theology, institute of theology, or theological union.
In the United States, a Protestant theological school that is not part of a university is often called a theological seminary or just a seminary. If, on the other hand, the school is part of a university, the more common name is divinity school.
In Canada, Britain, and elsewhere in the English-speaking world, a theological school is often called a theological college or simply a college or even a hall. Many Canadian and British theological colleges are independent but have a loose affiliation with a nearby "secular" university. In some cases, multiple theological colleges that represent different faith traditions are affiliated with the same university.
There are many variations on these names, including school for ministry, center, and school of divinity.
Generally, the head of a theological school is called a president. In Canada, a common synonym is principal. The head of a Catholic seminary is often called a rector. The head of an Episcopal seminary is usually called a dean. However, in most other theological schools, the dean is instead the chief academic officer. (At a college or university, the chief academic officer is usually called the academic dean or provost.)
The word "seminary"
Seminary sometimes refers to academic institutions that do not offer graduate theological education.
In the past, religiously affiliated secondary schools (especially for girls) were often called seminaries. Some secondary schools retain this name today.
In Catholic education, a minor seminary is a boarding school for high-school boys who are being trained for the priesthood. Traditionally, graduates of minor seminaries enrolled in the college department of a major seminary, where they pursued studies in a bachelor's-level "pre-theology" program. Today, there are few minor seminaries remaining in the United States and Canada.
Teenagers who are members of the Church of Jesus Christ of Latter-day Saints (the Mormons) often attend a religious instruction program before the start of their regular high-school classes each day. This program, often held at a nearby Mormon home or church building, is called early morning seminary or daily seminary.