It has neck and defines it perhaps (6)
I believe the answer is:
bottle
'it has neck and defines it perhaps' is the definition.
The definition suggests a singular noun which matches the answer.
This is all the clue.
Can you help me to learn more?
(Other definitions for bottle that I've seen before include "Type of marine mammal" , "Grit" , "Jeroboam" , "Glass or plastic container" , "Glass container - firmness of resolve" .)
