medley vs pastiche

medley and pastiche both are nouns.

Word	Noun	Adjective	Verb	Adverb
medley	Yes	No	No	No
pastiche	Yes	No	No	No

As nouns, medley and pastiche are synonyms defined as:

medley and pastiche: a musical composition consisting of a series of songs or other musical pieces from various sources

Other synonyms of medley include potpourri.

medley (noun)	pastiche (noun)
a musical composition consisting of a series of songs or other musical pieces from various sources	a work of art that imitates the style of some previous work
	a musical composition consisting of a series of songs or other musical pieces from various sources