One more time (5)
(Other definitions for twice that I've seen before include "Double in quantity" , "Doubly" , "Two times" , "You only live -- (film)" .)
'one more time' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for again that I've seen before include "Anew" , "Furthermore" , "Here we go ___" , "'Another time, once more (5)'" , "Ocne more" .)