Passage for one from Oslo (4)
I believe the answer is:
solo
'passage' is the definition.
(I have seen 'Unaccompanied passage ' mean 'solo' so perhaps 'passage' could also mean 'solo')
'one from oslo' is the wordplay.
'one from' indicates an anagram (the anagram comes from the same letters).
'oslo' with letters rearranged gives 'SOLO'.
'for' is the link.
(Other definitions for solo that I've seen before include "One-person performance" , "Han - (Star Wars); fly unaccompanied" , "Done by one person" , "Piece for one performer" , "Fly aircraft" .)