The term 'Viol Precursor' is a crossword solution that can be filled in with the word 'Rebec', which is a five-letter word. The Rebec is a stringed instrument that was popular in Europe during the Middle Ages and Renaissance periods. It is believed to have originated in the Middle East and was brought to Europe by the Moors. The Rebec is a bowed instrument that has three strings and is played with a bow. It is similar to a violin, but smaller and with a different sound.