rain check vs ticket stub

rain check and ticket stub both are nouns.

Word	Noun	Adjective	Verb	Adverb
rain check	Yes	No	No	No
ticket stub	Yes	No	No	No

As nouns, ticket stub is a hypernym of rain check; that is, ticket stub is a word with a broader meaning than rain check:

rain check: a ticket stub entitling the holder to admission to a future event if the scheduled event was cancelled due to rain
ticket stub: a torn part of a ticket returned to the holder as a receipt

Other hypernyms of rain check include stub.

rain check (noun)	ticket stub (noun)
a ticket stub entitling the holder to admission to a future event if the scheduled event was cancelled due to rain	a torn part of a ticket returned to the holder as a receipt
a promise that an unaccepted offer will be renewed in the future