I define success as widely and traditionally recognized, along the lines of reaching a goal or accomplishing something.
And if success is not achieved, I do like to have an opportunity to change my reaction or reformulate a plan when successes I sought to succeed in turn into failures or minimal accomplishments at the very least.
Learning something in the process is something I find quite valuable.
For example, a failed Swiss roll cake turned into a Gingerbread Trifle.
Successes makes for a celebratory, joyous occasion. Failures turn into occasional frustration and I look for ways to reach for creativity, moments of laughter, and additional opportunities to try again.