elk vs Cervus elaphus canadensis

elk and Cervus elaphus canadensis both are nouns.

Word	Noun	Adjective	Verb	Adverb
elk	Yes	No	No	No
Cervus elaphus canadensis	Yes	No	No	No

As nouns, elk and Cervus elaphus canadensis are synonyms defined as:

elk and Cervus elaphus canadensis: large North American deer with large much-branched antlers in the male

Other synonyms of elk include American elk, wapiti.

elk (noun)	Cervus elaphus canadensis (noun)
large northern deer with enormous flattened antlers in the male; called `elk' in Europe and `moose' in North America	large North American deer with large much-branched antlers in the male
common deer of temperate Europe and Asia
large North American deer with large much-branched antlers in the male