The distance between two notes (keys) is called the interval (which comes from the Latin “inter” meaning between and “vallum” meaning wall).
The distance between two C’s (or A’s or E’s etc) equals 8 notes for eamble A, B, C, D, E, F, G and A. This interval of 8 notes is called the octave (from the Latin “octavus” meaning eight.
Viewed fro Middle-C we refere to the octaves as first octave left second octave left etc.
