Two questions that I am commonly asked are 'Why are the vocal cords so called? and 'Are they really ropes?'
Well, the vocal cords are muscles. The name of vocal cords goes back to the French doctor Antoine Ferrein (1693 - 1769) who at that time, experimenting on animal larynxes, was able to see them in vibration and later found that by stretching and releasing them while blowing in the trachea, different sounds heights were obtained. Having verified this, he decided to associate this mechanism with that of the strings of the viola da gamba, thinking that the setting in vibration occurred by 'rubbing' by the air, as instead happens in the viola with the rubbing of the bow and that the lungs and chest did instead of the hand that moves the bow. These muscles have since been called and continue to be called vocal cords.