catchword

noun

1. a favorite saying of a sect or political group

   noun.communication

   Synonyms motto shibboleth slogan

   Source: WordNet 3.0

2. a word printed at the top of the page of a dictionary or other reference book to indicate the first or last item on that page

   noun.communication

   Synonyms guide word guideword

   Source: WordNet 3.0

3. Among theatrical performers, the last word of the preceding speaker, which reminds one that he is to speak next; cue.

   noun

   Source: webster1913