cross-index vs cross-reference

cross-index and cross-reference both are nouns.

Word	Noun	Adjective	Verb	Adverb
cross-index	Yes	No	Yes	No
cross-reference	Yes	No	No	No

As nouns, cross-index and cross-reference are synonyms defined as:

cross-index and cross-reference: a reference at one place in a work to information at another place in the same work

cross-index (noun)	cross-reference (noun)
a reference at one place in a work to information at another place in the same work	a reference at one place in a work to information at another place in the same work

cross-index (verb)	cross-reference (verb)
make an index that refers from one point to the next