Definition: small flat backed wire-strung plucked instrument; played with a plectrum; popular from renaissance to baroque times. Modern citterns are much bigger, and more like mandolins in shape. Usually with 10 strings in 5 courses. Related to Portuguese Guitarra. Read the full Citterns FAQ Page.
Round-neck resonator guitars are generally played in the normal guitar position. Sometimes fretted normally but often played with a 'slide' or 'bottleneck' instead.