Cross vs emblem

Cross and emblem both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cross	Yes	No	No	No
emblem	Yes	No	No	No

As nouns, emblem is a hypernym of Cross; that is, emblem is a word with a broader meaning than Cross:

Cross: a representation of the structure on which Jesus was crucified; used as an emblem of Christianity or in heraldry
emblem: special design or visual object representing a quality, type, group, etc.

Cross (noun)	emblem (noun)
a representation of the structure on which Jesus was crucified; used as an emblem of Christianity or in heraldry	special design or visual object representing a quality, type, group, etc.
	a visible symbol representing an abstract idea