I can't believe nobody looked at the title and didn't say the obvious. A flop is a FLoating point OPeration.

Now to add to the thread, which I merely skimmed through so I could easily be restating something. To me there are two possible ways a game can flop. Almost universally a game flops when it fails to turn a profit OR fails to generate more revenue than another project would have done(Opportunity cost).

But there are a few games that are intended more as pieces of art. Usually smaller projects that are far more niche than mainstream. They're designed not to require much in terms of sales to be "worth" the effort, but these flop when they don't garner media/public acclaim. Wii Music would probably be a great example of this type of flop, as it undoubtedly turned a huge profit, but has been blasted all over the place(though plenty of customers have loved it as well).

When a game does not make its budget back.

There are so many variables for this.

If a game is hyped to the level of Halo 3 or Killzone 2 it better sell at least 2 million lifetime.

If a game isn't highly anticipated then as long as it sells a respectable 750k (wii) or 500k (PS3/360) then I don't think you can really call it a flop.

I think it depends on how many copies are shipped and how much money is made.

??

a flop for me is when the game sucks ass, dont care about sales when i am playing...