Simple Explanation

The lowest and main tone you hear in a sound—it gives the sound its basic pitch.

Concise Technical Definition

The lowest frequency in a harmonic series, corresponding to the primary pitch of a sound or the first harmonic of a vibrating system.

Layman-Friendly Analogy

Like the root of a tree—everything else (harmonics) grows from it, but the root defines the sound.

Industry Usage Summary

In music, acoustics, and audio analysis, the fundamental determines the pitch we perceive; all other harmonics or overtones are built on top of it.

Engineering Shortcut

First harmonic; base frequency of vibration or waveform.

Full Technical Explanation

The fundamental frequency is the lowest frequency produced by any vibrating system and is the first harmonic in a harmonic series. In musical terms, it defines the perceived pitch of a note. All other harmonics (overtones) are integer multiples of the fundamental. For example, if a vibrating string produces a tone at 100 Hz, that’s the fundamental; 200 Hz, 300 Hz, etc., are its harmonics. In sound synthesis and analysis, accurately identifying the fundamental is critical to understanding timbre, tone, and pitch perception. In audio systems, equipment must accurately reproduce the fundamental to maintain musical integrity.