Final part (3)
'final part' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for end that I've seen before include "Remainder" , "ambition" , "Conclusion, finish" , "Unyielding" , "Discontinue" .)
'final part' is the definition.
(something's tail end is its last part)
This is the entire clue.
(Other definitions for tail end that I've seen before include "Very last part" , "Hindmost part" , "like late Charlie?" , "Final part" , "Last throes" .)