Since, the notes in music theory (A-G) are cyclic, how do tell which key is higher and which one lower?

Question

Since, the notes in music theory (A-G) are cyclic, how do tell which key is higher and which one lower?

In: Other

Answer 1

To distinguish octaves, notes are written with their tone and octave. A C4 is middle C, and the one above is C3, and the G in between is G4.

Edit: Ahhhhhh! I messed up (thanks to u/rubsub for pointing it out). The octaves go the other direction, so a C3 is the octave below C4, and C5 is the octave above.