Etymology of word "Octave"?

Question

How come the etymology of the word octave is related to the number *eight*, when the numbers that you would associate with the meaning of the word are either two – doubling of the frequency – , or alternatively five, seven, or twelve, if we think about the number of notes within commonly used scales, starting from any note and stopping one octave higher? Etymology dictionaries don't help as they simply point out the Latin root of the word - Related to the number eight – and also the Wikipedia article doesn't seem to mention anything about this. My question is thus about why the number eight is anything special in dividing up one cycle of unique pitches , since it ("8") is only relevant for the diatonic scale , which is itself salient only in western cultures, and even there with strong competition from other scale types such as the chromatic or pentatonic. Why, then, is the interval that doubles the pitch not called a pent for instance?

Answer 1

The word "octave" refers to the number eight because usually the eighth note in a scale is when the root repeats at a different pitch. For example:

C Major Scale: C D E F G A B (C)

Scale Degrees: 1 2 3 4 5 6 7 (8)

Major Scale Intervals: root, major 2nd, major 3rd, perfect 4th, perfect 5th, major 6th, major seventh, (octave)

A Minor Scale: A B C D E F G (A)

Scale Degrees: 1 2 b3 4 5 b6 b7 (8)

Minor Scale Intervals: root, minor 2nd, minor 3rd, perfect 4th, perfect 5th, minor 6th, minor seventh, (octave)

From your description it seems like you might know this already, and perhaps there's a more fitting word, but this is the one in standard practice within Western music. Hope that helps!

-Nic

-Nic