~ Grammar ~ One of the seven liberal arts and sciences which forms, with Logic and Rhetoric, a triad dedicated to the cultivation of a language. "God," says Sanctius, "created man the participant of reason; and as He willed him to be a social being, He bestowed upon man the gift of language, in the perfecting of which there are three aids. The first is Grammar, which rejects from language all solecisms and barbarous expressions. The second is Logic, which is occupied with the truthfulness of language. And the third is Rhetoric, which seeks only the adornment of language."

~ Rhetoric ~ The art of embellishing language with the ornaments of construction so as to enable the speaker to persuade or affect his listeners. It supposes and requires a proper acquaintence with the rest of the liberal arts. The first step toward adorning a discourse is for the speaker to become thoroughly familiar with his subject ~~ hence, the ancient rule that the orator should be acquainted with all of the arts and sciences. It is described in the Ancient Constitutions as "retoricke that teacheth a man to speake faire and in subtill termes."

~ Logic ~ Logic is the art of reasoning, whose uses are emphasized throughout Freemasonry. The power of accurate reasoning is deemed essential to the Freemason so that he may comprehend both his rights and his duties to God, to himself and his family, to his community, and to the Fraternity. The Old Charges define logic to be the art "that teacheth to discern truth from falsehood."

~ Arithmetic ~ That science which is engaged in considering the properties and powers of numbers, and which, from its manifes necessity in all the operations of weighing and measuring, must have had its origin in the remotest ages of the world. For the Freemason, the application of this science is that he is continually to add to his knowledge, never to subtract anything from the character of his neighbor, to multiply his benevolence to his fellow-creatures, and to divide his means with those in need.

~ Geometry ~ In modern ritual, Geometry is said to be the basis on which the superstructure of Freemasons is erected. In the Old Constitutions of the Medieval Freemasons, the most prominent place of all the sciences is given to Geometry. In our Ancient Constitutions, it is stated that "it teaches a man to mete and measure of the Earth and other things, which science is Masonrie."

~ Music ~ Music is recommended to the attention of Freemasons because as the "concord of sweet sounds" elevates the generous sentiments of the soul, so should the concord of good feeling reign among the Brethren, that by the union of friendship and Brotherly Love, the boisterous passions may be lulled and harmonry exist throughout the Craft.

~ Astronomy ~ The science which instructs us in the laws that govern the heavenly bodies. Its origin is lost in the mists of antiquity. From Astronomy many of Freemasonry's most significant emblems are borrowed. The Lodge itself is a representation of the world. It is adorned with images of the sun and moon, whose regularity and precision furnish us with a lesson of wisdom and prudence.

The above descriptions of the Seven Liberal Arts and Sciences Of Freemasonry
were taken directly from Mackey's Revised Encyclopedia.
Mackey's compilation is considered by many to be one of the
most authoritative sources of information on this topic.