The neck joint or heel is the point at which the neck is either bolted or glued to the body of the guitar. Almost all acoustic steel-string guitars, with the primary exception of Taylors, have glued (otherwise known as set) necks, while electric guitars are constructed using both types. Most classical guitars have a neck and headblock carved from one piece of wood, known as a "Spanish heel." Commonly used set neck joints include mortise and tenon joints (such as those used by C. F. Martin & Co.), dovetail joints (also used by C. F. Martin on the D-28 and similar models) and Spanish heel neck joints, which are named after the shoe they resemble and commonly found in classical guitars. All three types offer stability.

I have heard how giving you are in so many respects of music schooling and I must say that I am impressed. You remind me of the pure idealism that we had in starting Apple. If I were young, with time, I'd likely offer to join and help you in your endeavours. Keep making people happy, not just in their own learning, but in the example you set for them. 
Certain guitar brands are renowned and respected worldwide, and you don't have to be a player to be aware of them. Companies like Fender, Gibson, Epiphone, Ibanez, Yamaha and many others have built a solid reputation for providing exceptionally crafted guitars. In fact, these names are consistently endorsed by the greatest players of all time. However, you'll find more than enough guitar brands from lesser known manufacturers as well; these smaller companies take enormous pride in offering models of equally extraordinary playability, tone and construction.
Guitar Chords are a group of at least 3 notes played together, this means three different notes, i.e. notes with 3 different pitches. If, for example, you select an E major chord on the guitar chord generator on this page, you can see the 3 notes E, B and G# (Ab) make up this chord. Some notes can be expressed as either sharp or flat (enharmonic spelling), the notes sound just the same but the naming of them is decided by which key the song is in. You can find out more about this in our music theory section.
Guitars have been played since the Renaissance era, after descending from the ancient Greek instrument, the kithara. Or, at least, that's how the theory goes: the only real proof for this is the similarities between the Greek word and the Spanish word, quitarra. Early guitars often had four strings, evolving into the six-string version we know today in the late 1600s. Anton Stradivari, the famous violin-maker, also had a hand in making guitars. There's now only one Stradivarius guitar left in existence.