Music originally for ukulele, finally using lute regularly? (5)
I believe the answer is:
fugue
'music' is the definition.
(fugue is a kind of music)
'originally for ukulele finally using lute regularly?' is the wordplay.
'originally' indicates taking the first letters.
'finally' suggests the final letters.
'regularly?' means one should take alternating letters (regularly take one letter, leave next etc.).
The first letters of 'for ukulele' is 'fu'.
The last letter of 'using' is 'g'.
The alternate letters of 'lute' are 'ue'.
'fu'+'g'+'ue'='FUGUE'
(Other definitions for fugue that I've seen before include "One musical form ..." , "Form of musical composition" , "Musical composition with a theme repeated and developed" , "Composition involving a repeated interwoven melody" , "Yearly records" .)