Trivium (liberal arts)

The word trivium, from Latin, is made of two parts. The first part "tres" meant "three" and the second part "vía" meant "way". 
In antiquity and the High Middle Ages, there were different ways of teaching young men at the university. The trivium was three simplest ways to study the world, and so young men learned them first. After the trivium, they studied the quadrivium. Together, these subjects were called the seven liberal arts. The most difficult, and final subject studied was theology.
The three subjects were related to talking about the world. These subjects were grammar, logic and rhetoric. They were ways of preparing for the quadrivium, which includes arithmetic, geometry, music and astronomy.
Grammar.
One way of studying the world is to look at the form of the words. Grammar is the mechanics of the language.
When a man studied grammar, he studied how words were put together, and how words were combined to make sentences, paragraphs, chapters, and stories.
The word "grammar" has a more limited meaning now than it did before now. Many subjects, such as syntax and phonetics were part of grammar.
Logic.
One way of studying the world is to look at the meaning of words. Logic is the mechanics of thought and analysis. Logic is the study of how meanings are related to each other, and how to make good decisions. A fallacy is when someone does not draw a conclusion according to the rules of logic. An old name for logic was dialectics.
Rhetoric.
One way of studying the world is to look at communicating with words. Rhetoric is the mechanics of discourse. Discourse is the process of two or more people communicating about an idea. Young men studied rhetoric in order to learn how to instruct and to persuade.