Is the other one the mandolin?
The early 17th century Caribbean slaves brought with them and played a native African instrument made from a half of a gourd with a skin top that had 2-3 strings strung on a long stick attached to the gourd.
After arriving in America, the instrument was slowly modified over the years into a 4 string, 5 string and 6 string wooden bowled, skin topped instrument with a neck and frets - the name the early American slaves and other musicians called it evolved from several possible African words, but eventually it became known as the banjo.
The mandolin comes mostly from the Greek bouzouki, which comes from the lute.
A bouzouki has a longer neck, a lower pitch and a different tuning, and can have six strings in 2 sets of 3 strings that are tuned and fretted together in the groupings of 3 strings, or 8 strings played in sets of 2 two strings that are tuned and fretted together in the groups of 2 strings - the latter being the same stringing style of the mandolin, and the most commonly found and played type of bouzouki.
An octave mandolin also has the same long neck, and is basically identical to the the bouzouki scale wise, but is tuned the same as a mandolin, only an octave lower in pitch, and has twice the octave range of a standard mandolin.
Well, that does it for my Ted Talk tonight, and thank you all for coming!
We now return you to your regularly scheduled programming.