Luck is the phenomenon and belief that defines the experience of improbable events, especially improbably positive or negative ones.The naturalistic interpretation is that positive and negative events may happen at any time, both due to random and non-random natural and artificial processes, and that even improbable events can happen by random chance. In this view, the epithet "lucky" or "unlucky" is a descriptive label that refers to an event's positivity, negativity, or improbability.
Source: The school of life