The trivium is the lower division of the seven liberal arts and comprises grammar, logic, and rhetoric.[1]
The trivium is implicit in De nuptiis Philologiae et Mercurii (“On the Marriage of Philology and Mercury”) by Martianus Capella, but the term was not used until the Carolingian Renaissance, when it was coined in imitation of the earlier quadrivium.[2] Grammar, logic, and rhetoric were essential to a classical education, as explained in Plato’s dialogues. The three subjects together were denoted by the word trivium during the Middle Ages, but the tradition of first learning those three subjects was established in ancient Greece.
Source: Trivium – Wikipedia
Tim B.
“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 (numbers as abstract concepts), geometry (numbers in space), music (numbers in time), and astronomy (numbers in space and time). Educationally, the trivium and the quadrivium imparted to the student the seven liberal arts of classical antiquity.[1]”
Tim B.
“Sister Miriam Joseph, in The Trivium: The Liberal Arts of Logic, Grammar, and Rhetoric (2002), described the trivium as follows:
Grammar is the art of inventing symbols and combining them to express thought; logic is the art of thinking; and rhetoric is the art of communicating thought from one mind to another, the adaptation of language to circumstance. “
Tim B.
https://en.wikipedia.org/wiki/Liberal_arts_education#Seven_liberal_arts