Giro sent back home for start (6)
I believe the answer is:
origin
'start' is the definition.
(I've seen this in another clue)
'giro sent back home' is the wordplay.
'sent back' is a reversal indicator.
'home' becomes 'in' ('he's home' can mean 'he's in').
'giro' back-to-front is 'orig'.
'orig'+'in'='ORIGIN'
'for' acts as a link.
(Other definitions for origin that I've seen before include "Source - provenance" , "spring" , "First thing" , "Where one begins" , "Place or point of beginning (6)" .)