A "riff" is a short, catchy musical phrase or pattern that is repeated throughout a song. It usually stands out and helps create the main melody or groove of a song. Full definition
We went on riff on the psychology of the characters in THE LAST WORD, muse on making an entertaining film with substance, and the legacy of the women's movement. (killermoviereviews.com)
Much of The Good Dinosaur's humor rises from a series of riffs on western movies, keeping adults amused while tickling children with such sight gags as a cowboy T. rex using a cricket as a harmonica as he unwinds by the campfire. (shepherdexpress.com)
These little irritating things like the music score playing over and over (the same guitar riffs on a loop will eventually drive you insane), characters repeating themselves, and saying things like: «My role is to see the hidden truth that lies beneath each battle» just seem a little bit silly to me and decrease the overall experience of the game, unless you turn the music off and skip most of the dialogue. (nonfictiongaming.com)