A "Lick" is a stock pattern or a phrase. They consist of a short series of notes that can be re-used in improvisation or accompaniment. Licks can be adapted to be used over any chord or progression. You can play the licks exactly as written, or you can take the phrasing from a lick (note choices) and apply them to other notes. You can also change the rhythm or timing of a lick, keeping the same notes, but executing it differently. Licks are just springboards for exploration, and may hint you towards a certain way of thinking. They will expand your improvisation vocabulary, and also enable you to sound convincing even when the inspiration hasn't kicked in yet.