The Collaborative International Dictionary of English v.0.48:

Venture \Ven"ture\ (?; 135), n. [Aphetic form of OE. aventure.
   See Adventure.]
   1. An undertaking of chance or danger; the risking of
      something upon an event which can not be foreseen with
      certainty; a hazard; a risk; a speculation.
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            I, in this venture, double gains pursue. --Dryden.
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   2. An event that is not, or can not be, foreseen; an
      accident; chance; hap; contingency; luck. --Bacon.
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   3. The thing put to hazard; a stake; a risk; especially,
      something sent to sea in trade.
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            My ventures are not in one bottom trusted. --Shak.
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   At a venture, at hazard; without seeing the end or mark;
      without foreseeing the issue; at random.
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            A certain man drew a bow at a venture. --1 Kings
                                                  xxii. 34.
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            A bargain at a venture made.          --Hudibras.
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   Note: The phrase at a venture was originally at aventure,
         that is, at adventure.
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