- The higher division of the seven liberal arts in the Middle Ages, composed of geometry, astronomy, arithmetic, and music.
- A place where four ways meet.
- The collective name of the four branches of mathematics according to the Pythagoreans—arithmetic (treating of number in itself), music (treating of applied number), geometry (treating of stationary number), and astronomy (treating of number in motion).
- The four “liberal arts,” arithmetic, music, geometry, and astronomy; -- so called by the schoolmen. See <xref urlencoded="trivium">trivium</xref>.
- The higher division of the seven <xref>liberal arts</xref> in the <xref>Middle Ages</xref>, composed of <xref>geometry</xref>, <xref>astronomy</xref>, <xref>arithmetic</xref>, and <xref>music</xref>.
- (Middle Ages) a higher division of the curriculum in a medieval university involving arithmetic and music and geometry and astronomy