Watch the Playing on the G String online guitar lesson by David Hamburger from Blues Guitar For Beginners
The words riff, lick and solo each mean something slightly different. A solo is an entire improvisation, usually played over at least one time through a form like the twelve bar blues. A solo may include several licks, or specific shorter improvised (or memorized) ideas or phrases. A riff is more structural than a solo or a lick; it's a specific phrase that gets repeated at various points throughout the song to help frame the vocals or the chord progression of the song.
>>Greatest Rock Riffs