Pronunciation: (kach'līn"),[key] —n. 1. a word, phrase, or sentence used, esp. in advertising or journalism, to arouse or call attention.
2. a line in which a catchword appears.
3. a line of lesser importance, set shorter or sometimes in smaller type than the lines above and beneath it.
4. Theat.a line of comic dialogue expected to elicit laughter.
5. slug1 (def. 10a).