stag vs American elk

stag and American elk both are nouns.

Word	Noun	Adjective	Verb	Adverb
stag	Yes	No	Yes	No
American elk	Yes	No	No	No

As nouns, American elk is a hypernym of stag; that is, American elk is a word with a broader meaning than stag:

Other hypernyms of stag include Cervus elaphus, elk, red deer, wapiti.

stag (noun)	American elk (noun)
adult male deer	large North American deer with large much-branched antlers in the male
a male deer, especially an adult male red deer	common deer of temperate Europe and Asia

stag (verb)	American elk (verb)
watch, observe, or inquire secretly
give away information about somebody
attend a dance or a party without a female companion