What is a versatile plucked string instrument with body shaped like half pear popular during the Renaissance?

The instrument you are describing is called a lute. It is a fretted string instrument that was popular in Europe during the Renaissance and Baroque periods. Lutes have a body that is shaped like half a pear, and they are typically played by plucking the strings with a plectrum. Lutes can have anywhere from four to 24 strings, and they are capable of producing a wide variety of sounds.