Mid (7)
(Other definitions for twixt that I've seen before include "Between (archaic)" , "dividing" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">mid</span>' is the definition.<br/ ><span class="explanation-format__explanation">(thesaurus)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for central that I've seen before include "Middle; crucial" , "Near the middle" , "Focal" , "Most important, principal" , "Key" .)