In music, a chord is a group of three or more musical notes sounded simultaneously to produce harmony. In geometry, it is a straight line joining two points on the circumference of a circle.

A chord is a number of musical notes played or sung at the same time with a pleasing effect. (Collins Dictionary)

In other words, a chord is a beautiful music whose pleasing effect is harmonious. The term 'harmony' implies the axis mundi: the centre of the world.

Our world revolves around the earth. The earth is divided into two equal halves by a circle known as the equator. The two halves are the northern hemisphere and the southern hemisphere. This means that the world is a sphere.

A sphere is a three dimensional structure like a cube. Without depth, a sphere is a circle and a cube is a square.

Therefore the world is a circle and the equator dividing the world into two equal halves is the diameter of the circle. The northern hemisphere and the southern hemisphere are two semicircles.

In geometry, a chord can either divide a circle into two equal halves or two unequal halves. If the chord divides a circle into two unequal halves, the circle is chaos or judgement. But if the chord divides the circle into two equal halves, the circle is harmony or non-judgment.

Since the diameter of a circle is a chord dividing the circle into two equal halves, the diameter is the geometric reflection of the musical definition of a chord.

The earth is full of different kinds of sounds. A sound could be an ideology, religious teachings, tradition or culture.

Two or more sounds constitute harmony if they agree. But each sound is a noise if they disagree. The two sounds are two lines whose point of agreement is the diameter. Though there are three lines, the third line is the product of the other two lines.

Each of the two lines constituting the third line is a noise. Example: Islam and Christianity are two lines where Islam is a noise to the Christians and Christianity is a noise to the Muslims. But the hybrid formed when Islam and Christianity are cross-bred is a pleasant sound enjoyable by Muslims and Christians alike. The sound is the chord.