Gland in the neck (7)
I believe the answer is:
thyroid
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">gland in the neck</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for thyroid that I've seen before include "Growth-controlling gland" , "Gland in the neck" , "Growth-regulating gland" .)