The second-largest city in Oklahoma (5)
I believe the answer is:
tulsa
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">the second-largest city in oklahoma</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 tulsa that I've seen before include "Oklahoma city (only 24 hours away?)" , "Major oil centre" , "A lust for the Oklahoma oil city?" , "Twenty-four Hours from - (Gene Pitney)" , "Oklahoma river port" .)