Stringed musical instrument (5)
(Other definitions for cello that I've seen before include "String quartet instrument" , "Played by Rostropovich" , "Large stringed instrument" , "Jacqueline du Pre's instrument" , "big fiddle?" .)
(Other definitions for banjo that I've seen before include "Stringed instrument like guitar with round body" , "Stringed instrument beloved of old minstrel shows" , "Formby's instrument" , "Small plucked instrument" , "Relative of the guitar" .)