Luck could be anything, it could be big, it could be small, you could be ready, or not ready, it could be a loss, it could be a profit. I mean anything could be considered as luck, and you just have to try to explain it some other way to put it on paper, otherwise everything is just luck. If you really want to put it as luck, then every profit ever made was luck, no matter how hard someone worked to find a good trade, just say that "you got lucky that your research turned out to be true, you could have been wrong" and suddenly tens of hours, even hundreds of hours of work could put down as just pure luck.