doubleheader vs twin bill

doubleheader and twin bill both are nouns.

Word	Noun	Adjective	Verb	Adverb
doubleheader	Yes	No	No	No
twin bill	Yes	No	No	No

As nouns, doubleheader and twin bill are synonyms defined as:

doubleheader and twin bill: two games instead of one (especially in baseball when the same two teams play two games on the same day)

Other synonyms of doubleheader include double feature.

doubleheader (noun)	twin bill (noun)
two games instead of one (especially in baseball when the same two teams play two games on the same day)	two games instead of one (especially in baseball when the same two teams play two games on the same day)