An Octave is a note that is 8 notes away higher or lower. For instance, on guitar there are many places to play an A. Each A would be in a different octave. For instance, if you play the open A string that is an A. If you play the A string on the 12th fret, that is also an A but an Octave higher. This would be an octave pair or octave shape. Octave shapes can be helpful for navigating where notes are on the fretboard.
When talking about guitar, you will often see the acronym CAGED. In the case of octave shapes, we will use this acronym. Think of each letter in CAGED as a chord shape. For instance, the basic C chord shape, we get the following octaves.
If we look at the basic A chord shape, we get the following octaves:
If we look at the basic G chord shape, we get the following octaves:
If we look at the basic E chord shape, we get the following octaves:
If we look at the basic D chord shape, we get the following octaves:
With the above information, you could slide any of the octave shapes around the neck to other keys to form other octave pairs.
Some other common octave shapes would be:
