Band around the neck (6)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">band around the neck</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for collar that I've seen before include "Apprehend (someone)" , "Item worn around the neck" , "Seize; cut of bacon" , "Neckband to seize" , "Apprehend (colloq.); cut of bacon" .)