elk vs Alces alces

elk and Alces alces both are nouns.

Word	Noun	Adjective	Verb	Adverb
elk	Yes	No	No	No
Alces alces	Yes	No	No	No

As nouns, elk and Alces alces are synonyms defined as:

elk and Alces alces: large northern deer with enormous flattened antlers in the male; called `elk' in Europe and `moose' in North America

Other synonyms of elk include moose.

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