I was walking down the hall of the University of Colorado College of Music with Brenda Romero, on my way to play for one of her ethnomusicology classes, when one of her colleagues joined us, looked at my guitar case, and asked, "Is that a cello?"
When I got home, I put my guitar, vertically, between my legs and looked at it. A cello is an "octave viola." Its lowest string is two C's below middle C. The next string up is the G, a fifth up. The guitar's low note is the E between them -- just two notes up from the cello's bottom. She was asking a sensible question -- guitars and cellos are roughly the same size and range. They're played so differently, that we don't tend to see the similarities.
Fiddles are violins. Non-musicians will sometimes ask the fiddler, "Is that a fiddle or a violin?" The different words are from different language families: "violin" is from French, "fiddle" from Old English, sort of a flavor of German. Ever since the Norman invasion, in 1066, we've used Romance-language words when we want to sound sophisticated and cultured, and Germanic words when we're bein' just folks. Nobles ate "beef" ("boeuf") and "pork" ("porc"), while the cattle maids and swineherds raised "cows" and "pigs" (German: "Kuh" and "Schwein") .
Other languages don't do this as much. If you ask Isaac Stern, who grew up speaking Yiddish (a Germanic language), he'll tell you he plays fiddle.
Mandolins? Fiddles with frets. Like guitars and fiddles, we just think of them differently, but the ranges are about the same.
So what the heck is a banjo?
I pulled out a banjo and an orchestration book. Believe it or not, the range is about the same as a viola.
So there you have it: a string band with a guitar, a banjo, and a pair of fiddles, or a fiddle and a mando, is just a string quartet with different voicing.
