Market or exchange (6)
I believe the answer is:
rialto
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">market</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">exchange</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for rialto that I've seen before include "Central area of Venice and suburb of Dublin" , "place of business" , "exchange" , "Island in Venice with famous bridge" , "Area famous for 7 [ABRIDGE]" .)