When it comes to casino terms, En Plein is as simple as it gets. The term is most often used in roulette and it refers to placing a plain bet and betting on a single number.
Considering the fact that there are numerous types of bets you can place in roulette, such as betting on odd or even numbers, red or black, and even number groups, it doesn’t come as a surprise that betting on a single number is referred to as placing a plain bet.
However, the term isn’t restricted only to the game of roulette. It can be used in other situations as well and it retains the same meaning. For example, betting on a single side, chance, or outcome can still be referred to as placing the En Plein bet.