What is failure?

Failure in my basic understanding is when expectations for any given project or goal is not met. It's when where you want to be falls behind where you want to be. Now that by itself is not necessarily failure. In my opinion failure is when this expectation falls so far behind the goal that it is no longer recoverable, whatever you goal was in no longer obtainable. For example if a NASA rocket has issues and can not launch but it is only a delay to launch again other day I would not define that as failure. Now if the rocket explodes and can never have a chance to launch again then I would define that as failure. So all this is only my definition.

The Oxford English Dictionary defines failure as

 a. A failing to occur, be performed, or be produced; an omitting to perform something due or required; default.

Saying that failure is simply when something doesn't happen as or when its suppose to. Whatever is produced does not fulfill what it is suppose to. What was presented does not fill the need or the needed is not produced at all, it failed to occur.

and then sometimes