Harmonics refer to the frequencies of sound waves that are integer multiples of a fundamental frequency. When a musical instrument, like a guitar or a piano, produces a note, it generates not just the main frequency but also additional frequencies that contribute to the richness of the sound. These additional frequencies are called harmonics. In music, harmonics play a crucial role in defining the timbre or tone quality of an instrument. For example, a violin and a flute playing the same note will sound different due to their unique harmonic content. Understanding harmonics helps musicians and sound engineers create and manipulate sounds effectively.