The term 'Jazz Line' is a musical term used to describe a short, improvised solo or phrase that is repeated throughout a song. The crossword solution for this term is 'RIFF, ' which stands for 'repeated figure in folk music.' A riff is a short, catchy phrase that is repeated throughout a song and is often used to create a memorable hook. It is usually played on a guitar or keyboard and is often associated with jazz, blues, and rock music.