Number making a comeback in Salzburg on vacation? (4)
I believe the answer is:
song
'number' is the definition.
(musical number)
'a comeback in salzburg on vacation?' is the wordplay.
'a comeback' becomes 'on' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' is an insertion indicator.
'on vacation?' means to remove the middle letters (after the inside letters have vacated the word).
'salzburg' with its middle taken out is 'sg'.
'on' put inside 'sg' is 'SONG'.
'making' is the link.
Can you help me to learn more?
(Other definitions for song that I've seen before include "Ditty" , "Musical number" , "Vocal number" , "See 17" , "Something recorded by 26 [FACES] , for example" .)