Reactions: Rounds and Turns

[Pingwii]

Question about Reaction: it is stated that characters gain their reaction at the start of their turn, but that you can only use 1 reaction per round.

Does that mean that a character that has its initiative at the middle of a round, which is using a reaction gained during the last round will not be able to use its new reaction after its turn during this round but will need to wait the next round to use it ?

This interpretation seems the only possible with the rules as written, but it disadvantage all characters who are not the first one AND THE LAST one in the initiative order (since it is the only situation in which the use of reaction is not restricted since round and turn stack for them), which is really strange.

Thank you for your help.

[Franz Lunzer]

While yes, a round is typically from the beginning of the highest initiative to the end of the lowest initiative, for reactions that is misleading.

For reactions, the round is more like the duration of 1 round spells: starting at your turn and lasting until the start of your next turn.

Look at: Start Your Turn

Quote:

Many things happen automatically at the start of your turn— it’s a common point for tracking the passage of time for effects that last multiple rounds. At the start of each of your turns, take these steps in any order you choose:

• If you created an effect lasting for a certain number of rounds, reduce the number of rounds remaining by 1. The effect ends if the duration is reduced to 0. For example, if you cast a spell that lasts 3 rounds on yourself during your first turn of a fight, it would affect you during that turn, decrease to 2 rounds of duration at the start of your second turn, decrease to 1 round of duration at the start of your third turn, and expire at the start of your fourth turn.
  
• You can use 1 free action or reaction with a trigger of “Your turn begins” or something similar.
  
• If you’re dying, roll a recovery check (page 459).
  
• Do anything else that is specified to happen at the start of your turn.
  The last step of starting your turn is always the same.
  
• Regain your 3 actions and 1 reaction. If you haven’t spent your reaction from your last turn, you lose it—you can’t “save” actions or reactions from one turn to use during the next turn. If a condition prevents you from being able to act, you don’t regain any actions or your reaction. Some abilities or conditions (such as quickened and slowed) can change how many actions you regain and whether you regain your reaction. If you lose actions and gain additional actions (such as if you’re both quickened and slowed), you choose which actions to lose.

If you haven't used it, you can use the reaction from your last turn, right at the beginning of your turn, before you regain your reaction for "this round".

[Ediwir]

Your turn is your spot in initiative. You start your turn when the action goes to you, and you end your turn when you pass.
Your round is the unit of time between the start of your turn and the start of your next turn. There is no objective "round" anymore.