noun
1.
a. : a line containing a catchword
b. : a short line (as of less important words in a title or display advertisement) between lines that are longer and sometimes larger
c. : an identification line (as on a printer's proof or a manuscript)
2. : a phrase or sentence designed to catch attention especially in an advertisement or as a heading or title of a story, article, or newspaper item
3. : a line in a theatrical production expected to cause a laugh and often repeated as a gag