Bug is a gambling term used by both brick-and-mortar and online casino poker players and most of the time, it refers to the joker. However, keep in mind that if it’s used in poker, the term can refer to a wildcard that can only be used to form straights and flushes.
As a playing card, the joker is found in virtually every French standard 52-card playing deck. Furthermore, they can also be found in both Spanish and Italian suited decks, while they are excluded from stripped decks.
While it is present in most of the decks, the joker is often omitted from play. However, there are still numerous games that use decks that feature jokers, such as Gin Rummy, Go Fish, Crazy Eights, etc. Depending on the game you’re playing, jokers can have a different role. For example, they can be a wild card, which is the case in poker, or the highest-value trump card.