One thousand million (7)
I believe the answer is:
billion
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">one thousand million</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for billion that I've seen before include "1,000,000,000" , "A large number" , "One thousand million" , "One followed by nine zeros" .)