What's the term for the intervals between notes within a scale that produces a chord

Question

I probably described that poorly in the title, and I'm not even sure there is a word for what I'm thinking.

Lets say you're playing on just the white keys on a keyboard. C E G is C major, and D F A is D minor, the next chord after that. The number of steps between the notes in each chord is different, but they're the same number of notes within the scale apart.

Is there a word that describes the number of notes apart within a scale like that?

Answer 1

Sure is! These are called Intervals. It has to do with the number of "Scale Degrees" that separate two notes - basically, the number of notes you have to move through the scale from the first note to reach the second note (including the note you started on). These are worded "Second", "Third", "Fourth", "Fifth", "Sixth", "Seventh", "Octave" (Octave indicates an 8 note separation)

So, in your example:

• C to E is a third (because you have to go from C (1) -> D (2) -> E (3))
• E to G would also be a third (E -> F -> G)
• C to G is a fifth (C -> D -> E -> F -> G)

You get a bit more complicated if you consider more unusual notes. For instance, C to Eb would be a minor third, because it's only three half steps. A more exhaustive list of Interval names is located here, but these are the basics.

I hope this helps. Disregard if I've misunderstood your question =)

EDIT: Just to be more clear / complete here (in case wikipedia ever disappears ;)):

Number of half steps    Interval Name
0                       Perfect unison
1                       Minor second
2                       Major second
3                       Minor third
4                       Major third
5                       Perfect fourth
6                       Diminished fifth, or augmented fourth
7                       Perfect fifth
8                       Minor sixth
9                       Major sixth
10                      Minor seventh
11                      Major seventh
12                      Perfect octave