eli5: in music, since there are 12 notes per octave, why are only 7 letters used instead of 12?

Question

eli5: in music, since there are 12 notes per octave, why are only 7 letters used instead of 12?

In: 15

Answer 1

A scale only has 8 notes (7 distinct notes, because you count the root note twice.)

We named our notes off of the A major scale in the Aeolian mode, the notes of which are A B C D E F G (A)

Other scales include sharps or flats, but any given scale only has 7 different notes in it