The Trivium is a systematic method of critical thinking used to derive factual certainty from information perceived with the traditional five senses: sight, sound, taste, touch, and smell. In the medieval university, the trivium was the lower division of the seven liberal arts, and comprised grammar, logic, and rhetoric (input, process, and output).

Etymologically, the Latin word trivium means "the place where three roads meet" (tri + via); hence, the subjects of the trivium are the foundation for the quadrivium, the upper division of the medieval education in the liberal arts, which comprised arithmetic (number), geometry (number in space), music (number in time), and astronomy (number in space and time). Educationally, the trivium and the quadrivium imparted to the student the seven liberal arts of classical antiquity.

The trivium is implicit in the De nuptiis Philologiae et Mercurii ("On the Marriage of Philology and Mercury"), by Martianus Capella, although the term was not used until the Carolingian Renaissance, when the term was coined, in imitation of the earlier quadrivium. Grammar, logic, and rhetoric were essential to a classical education, as explained in Plato's dialogues. Together, the three subjects were included to and denoted by the word "trivium" during the Middle Ages, but the tradition of first learning those three subjects was established in ancient Greece. Contemporary iterations have taken various forms, including those found in certain British and American universities (some being part of the Classical education movement) and at the independent Oundle School, in the United Kingdom.

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