The theorbo is a plucked string instrument of the lute family, with an extended neck that houses the second pegbox. Like a lute, a theorbo has a curved-back sound box with a flat top, typically with one or three sound holes decorated with rosettes. As with the lute, the player plucks or strums the strings with the right hand while "fretting" the strings with the left hand.

Plucked string instruments are a subcategory of string instruments that are played by plucking the strings. Plucking is a way of pulling and releasing the string in such a way as to give it an impulse that causes the string to vibrate. Plucking can be done with either a finger or a plectrum.