Problems with this word is that; we don’t have a word in English that means “a well-reasoned attempt that didn’t meet expectation.”
Here are a few attempts to define mistakes:
» Misjudgments and adverse consequences that were unplanned. The scale of the consequences differentiates mistakes from lesser errors or slips.
» The failure of a planned sequence of mental or physical activities to achieve
its intended outcome when these failures can’t be left to chance.
It is important to notice that, pointing any mistake is a judgement by someone, and hence can be misleading sometimes. It's our attitude that determins how we can convert mistakes into opportunities which draw useful learning for better performances in future.