crumb vs breadcrumb

crumb and breadcrumb both are nouns.

Word	Noun	Adjective	Verb	Adverb
crumb	Yes	No	Yes	No
breadcrumb	Yes	No	No	No

As nouns, breadcrumb is a hyponym of crumb; that is, breadcrumb is a word with a more specific, narrower meaning than crumb:

Other hyponyms of crumb include cracker crumbs.

crumb (noun)	breadcrumb (noun)
small piece of e.g. bread or cake	crumb of bread; used especially for coating or thickening
a person who is deemed to be despicable or contemptible
a very small quantity of something