A guitar riff is a short, repeated musical phrase that is usually played on the guitar. It is often used to introduce a song or to provide a transition between sections of a song. The term 'guitar LICK' is often used interchangeably with 'guitar riff'. A LICK is a more specific type of riff, usually consisting of a single phrase rather than a series of phrases. The crossword solution for the term 'guitar riff' is 'LICK', which is a four-letter word.