open sesame vs bidding

open sesame and bidding both are nouns.

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

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

Other hypernyms of open sesame include bid, command, dictation.

open sesame (noun)	bidding (noun)
any very successful means of achieving a result	a request to be present
a magical command; used by Ali Baba	(bridge) the number of tricks a bridge player is willing to contract to make
	an authoritative direction or instruction to do something