Vote against entering area in New York (3)
I believe the answer is:
nay
'vote against' is the definition.
(I've seen this in another clue)
'entering area in new york' is the wordplay.
'entering area' becomes 'a' (maths abbreviation. I am not sure about the 'entering' bit.).
'in' is an insertion indicator.
'new york' becomes 'ny'.
'a' inserted into 'ny' is 'NAY'.
Can you help me to learn more?
(Other definitions for nay that I've seen before include "Negative answer" , "Denial" , "even" , "In point of fact - a parliamentary vote against" , "disagreement" .)