Tenor vs Octave Electric

[bjshear]

I was wondering what exactly is the difference between a tenor electric guitar and electric octave mandolin?

I know an octave mandolin usually has double course strings, but I have seen many with just four strings instead of eight.

[bolannta]

The main difference is tuning.
Tenor guitars are most commonly tuned to viola tuning, CGDA, or Chicago tuning, the top four stings on a guitar, DGBE.
Octave mandolin tuning is an octave below mandolin and violin, GDAE.
Electric mandolin family instruments are made with single and double courses.
Eye Candy electric section

[mandroid]

Octave .. is like an Irish tuned tenor banjo, that and the Irish Zouk are GDAE.

[djweiss]

Given how easily you can adjust the tuning on these instruments, my opinion is that the biggest difference would be 4 vs 8 strings...