It was different to middle part (5)
I believe the answer is:
waist
'to middle part' is the definition.
(I've seen this before)
'it was different' is the wordplay.
'different' indicates an anagram (letters placed in a different order).
'it'+'was'='itwas'
'itwas' anagrammed gives 'WAIST'.
(Other definitions for waist that I've seen before include "Central part of body" , "Part of the trunk" , "Middle part of a ship" , "Middle part of the body" , "Ever-expanding middle" .)