Harmonics: Lightly touching the string with a fingertip at a harmonic node creates harmonics. Instead of the normal tone, a higher pitched note sounds. Each node is at an integer division of the string, for example half-way or one-third along the length of the string. A responsive instrument will sound numerous possible harmonic nodes along the length of the string.

Harmonics are marked in music either with a little circle above the note that determines the pitch of the harmonic, or by diamond-shaped note heads. There are two types of harmonics: natural harmonics and artificial harmonics (also known as "false harmonics").

Natural harmonics are played on an open string. The pitch of the open string is called the fundamental frequency. Harmonics are also called overtones. They occur at whole-number multiples of the fundamental, which is called the first harmonic. The second harmonic is the first overtone, the third harmonic is the second overtone, and so on.