A [[Reaction]] is a special Action taken in response to a trigger defined in the Reaction's description. You can take a [[Reaction]] on another creature's turn, and if you take it on your turn, you can do so even if you also take an Action, a [[Bonus Action]], or both. Once you take a [[Reaction]], you can't take another one until the start of your next turn. The [[Opportunity Attack|Opportunity Attack]] is a [[Reaction]] available to all creatures.