The story
From an incident which took place at the Casino de Monte-Carlo.
Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: The fallacy, most often believed by gamblers, that a past random event influences the outcome of a future random event, that is, that a run of even numbers at roulette means that there is a greater chance of an odd number next time. Full definition →
From an incident which took place at the Casino de Monte-Carlo.
Etymology from Wiktionary, CC BY-SA 4.0.