The last thing that may be turned? (4)
I believe the answer is:
tail
This clue might be a double definition.
'the last' is the first definition.
(thesaurus)
'thing that may be turned?' is the second definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
Can you help me to learn more?
(Other definitions for tail that I've seen before include "Caudal fin" , "Follow furtively like private detective" , "Follow the caudal appendage" , "Shadow" , "Rear appendage of animal" .)