catchword vs guide word

catchword and guide word both are nouns.

Word	Noun	Adjective	Verb	Adverb
catchword	Yes	No	No	No
guide word	Yes	No	No	No

As nouns, catchword and guide word are synonyms defined as:

catchword and guide word: 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

Other synonyms of catchword include guideword.

catchword (noun)	guide word (noun)
a favorite saying of a group, organization or individual	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
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