Different Meanings of Tone in Music

In music performance and notation, the word "tone" can mean many different things, spanning literal and conceptual terminology. Some common definitions of tone include:

1. A musical sound
2. A whole step — an interval equaling two semitones (or half-steps)
3. The quality or character of a sound

When Tone Refers to a Pitch

In Western music, a steady sound can be referred to as a musical tone. The tone is characterized most frequently by its pitch, such as "A" or "C," but it also includes timbre (the quality of the sound), duration, and even intensity (the dynamic of the sound). In many forms of music, different pitches are altered by modulation or vibrato.

For example, if a violinist plays an "E" and adds vibrato to the note, it is no longer a pure tone. It now has tiny modulations that might add warmth to the sound, but also alters its pitch. A pure tone has a sinusoidal waveform, which is a pattern of even and repetitive oscillation. The resulting sound is very even and steady. 

Tone as a Music Interval

Since a tone often refers to a pitch in music it can be translated into music steps as well. A whole step is made of two half-steps. For example, from C to D is a whole step, but from C to C-sharp and C-sharp to D is two half-steps. These can also be called "tones" or "semitones." A semitone is essentially a half of a tone or a half-step. 

Tone and the Quality of Sound

Tone can also refer to the unique difference between voices of the same instrument and the color or mood of the voice (not to be confused with timbre). On different instruments and in vocal music, a tone may be expressed in many different ways. On the piano, for example, a delicate tone will contrast with a sharp and jarring tone, made possible through technical aspects of piano performance.

A singer might vary her tone by altering the quality of her voice and making it soft and gentle at times or course at others. For many musicians, the ability to alter and manipulate their tone is an impressive skill that comes with practice and technical finesse.