Take a seat (3)
I believe the answer is:
sit
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">take a seat</span>' is the definition.<br/ ><span class="explanation-format__explanation">(sit down on a seat)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for sit that I've seen before include "Order dog to behave" , "(Of bird) stay on nest" , "Serve (on jury)" , "Take a pew, an exam" , "Perch" .)