open sesame vs means

open sesame and means both are nouns.

Word	Noun	Adjective	Verb	Adverb
open sesame	Yes	No	No	No
means	Yes	No	No	No

As nouns, means is a hypernym of open sesame; that is, means is a word with a broader meaning than open sesame:

Other hypernyms of open sesame include agency, way.

open sesame (noun)	means (noun)
any very successful means of achieving a result	to have the ability to produce a particular effect or achieve an end
a magical command; used by Ali Baba	an artifact (that is instrumental in accomplishing some end) for accomplishing some end
	considerable capital (wealth or income)