WOW is with or without a trade. Odd lots cannot trade without a round lot. So if you have to sell 50 shares of stock on the NYSE and the stock has traded 0 shares today, you will not get a fill on your order unless either a round lot trades or you change your order to WOW.
Thanks for the info qazmax. I also got another definition today that said it was with or without a print. I'm guessing that's for block trades that don't care if their trade is printed on time and sales.
WOW is the G-rated version of the exclamation the average daytrader lets out upon receiving his fill from the floor of the NYSE or Futures Exchange.