A term generally applied to the currents of thought prevalent among the Christian philosophers and theologians of Western Europe from the 9th to the 15th century.
It does not usually include Byzantine, Arabian, and Jewish thought of the same period.
The word Scholastic was inherited from ancient Greece and Rome, and in the Middle Ages was used to designate anyone belonging to the schools, i.e., the masters or teachers of the schools.
In time these teachers and writers developed a characteristic method of investigation and exposition, known as the Scholastic Method, which they applied both in philosophy and theology.
It has ever remained one of the distinctive traits of Scholasticism.
Another one of its distinguishing featureg is the close relation between philosophy and religion manifested in its literary products.
Moreover, Scholasticism was notably dependent on ancient philosophy, at first on Neo-Platonism and later on Aristotle, as well as on the Fathers of the Church, particularly Saint Augustine of Hippo.
Thus understood it extends from Eriugena to Occam.
However, the most typical Scholasticism is that of the 13th century when it attained its highest development and was represented by such thinkers as Saint Albertus Magnus, Saint Bonaventura, Saint Thomas Aquinas, and Blessed John Duns Scotus.
This is Scholasticism par excellence.
New Catholic Dictionary