fantasia

noun

1. Music.
   1. a composition in fanciful or irregular form or style.
   2. a potpourri of well-known airs arranged with interludes and florid embellishments.
2. fantasy(def 9).
3. something considered to be unreal, weird, exotic, or grotesque.

noun

1. any musical composition of a free or improvisatory nature
2. a potpourri of popular tunes woven freely into a loosely bound composition
3. another word for fancy (def. 13)