noun
Etymology: tag (I)
1.
a. : a final line (as in a play, story, joke) ; especially : one that serves to clarify a point or create a dramatic effect
always hesitated before delivering the tag line that stunned the audience
b. : a reiterated phrase identified with an individual, group, or product : slogan , catchword
song lyrics, jokes … and performers' tag lines became … part of the whole country's stock of knowledge — Joe Laurie
never wrote a tag line that didn't sell
2. : a cable running from a crane boom to a bucket for steadying the bucket