Narrow part of a bottle (4)
I believe the answer is:
neck
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">narrow part of a bottle</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for neck that I've seen before include "One may get it in it!" , "A hard one shows some nerve" , "and what is at the bottom of it" , "Isthmus; impudence (sl.)" , "Kiss amorously" .)