Notes are named after the first seven letters of the alphabet:
Notes get higher as we go up the alphabets. When we get to G we start again from A, but the second set of seven notes is higher than the first seven:
One cycle starting from any letter and ending on the same letter is called an octave. Notes that are an octave apart – above or below – share the same name.
Because tunes go down as well as up, it’s useful to learn to say the first seven letters of the alphabet backwards, like this: G, F, E, D, C, B, and A.