I think I should post a correction. While if you were looking guitarcentricly you might say that the C on 5th fret G string or 1st fret B string is middle C. In the western world of music middle C is defined as C4, which is matched to the guitar 3rd fret A string or 8th fret LowE string. This is because the LowE string on guitar is tuned standardly to E3 and the next C is C4 (the number group of the notes starts on C or commonly known as Do).
No offense to anyone posting incorrect information without knowing it's incorrect; it's nobody's fault to be unwittingly incorrect about something.
Cheers :)
