Chromatic vs Non-diatonic vs Accidental?

Question

I was wondering if all three of these terms: chromatic, non-diatonic, accidental, all mean the same thing?

Answer 1

Hi, they actually have different meanings.

Chromatic intervals are always half steps moving up or down with the similar name pattern (C, C#, D, D# etc). We'll see sharps for ascending, and flats on the descending movements.

Non Diatonic notes and chords are the ones not native to a certain diatonic key. For example FMaj7 is a diatonic chord in the key of C Major Scale, however Bb7 would be non diatonic chord as Bb or Ab are non diatonic pitch in this key.

Accidentals are general name for sharps, flats and natural signs. Kind of saying siblings, instead of saying brothers and sisters.

Best,

Evren.

Answer 2

Yes, these three terms are basically the same thing.

Non-diatonic refers to any pitch that does not fit within the normal pitches of a standard scale.

There are several different kinds of scales so it depends on the context whether the pitches are non-diatonic. For example, the non-diatonic pitches of a natural minor scale will be slightly different than a major scale or even a harmonic minor scale.

Chromatic comes from the Greek word chromos which means color and is another word for non-diatonic pitches.

In a narrower context it is typically used to refer to passages of consecutive notes where the pitches are all a half step apart.

Accidental is the overarching word for sharps, flats, and natural signs in music that are not within the original key signature. These are generally non-diatonic pitches.

Whether accidentals are diatonic to the scale or not can get a little blurry with minor scales as the key signature usually reflects the natural minor while melodic minor is prefer for composing melodies and harmonic for the harmonies--all of which have slightly different pitches. For example, an accidental may be diatonic to the harmonic minor scale being used but not a part of the written key signature.