I believe I have found an editing error in either the definition combat rounds or in the ready action. Or possibly a significant change in how ready works from previous editions of D&D. Either way strict reading of the rules leads to odd intepretations of the rules.
The definiton of a Round (as per Player's D&D Basic Rules v2):
A round represents about 6 seconds in the game world. During a round, each participant in a battle takes a turn. The order of turns is determined at the beginning of a combat encounter, when everyone rolls initiative. Once everyone has taken a turn, the fight continues to the next round if neither side has defeated the other.
So by the above definition, a round is about 6 seconds where every character gets one turn. The round starts when the person with the highest initiative takes their turn and ends when the person with the lowest initiative takes their turn. There is also a sidebar which re-iterates this.
Excerpts from the Ready action (as per Player's D&D Basic Rules v2):
Sometimes you want to get the jump on a foe or wait for a particular circumstance before you act. To do so, you can take the Ready action on your turn so that you can act later in the round using your reaction. [Defintion of Triggers] When the trigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger. Remember that you can take only one reaction per round.
1): The last sentence in the ready action is incorrect as per the defintion of a round as defined above. The definition of a reaction is that once you've used a reaction, you can not use another before the start of your next turn.
2) A character may not ready an action for the next round as they won't be able to respond to triggers out side of the round the ready action was taken in. I don't believe this is the intent of the game. A character acting at a low intiative should be able to ready a reaction to respond to a character acting at a higher intiative in the next round. The key problem is the phrase "you can act later in the round" and that there is no other description of when you're no longer allowed to react to a readied trigger.
In previous editions, a round was less strictly defined but could be described as: "from the start of your turn to the start of your next turn". For example the D20 SRD has this statement in the combat rounds section:
For almost all purposes, there is no relevance to the end of a round or the beginning of a round. A round can be a segment of game time starting with the first character to act and ending with the last, but it usually means a span of time from one round to the same initiative count in the next round. Effects that last a certain number of rounds end just before the same initiative count that they began on.
I imagine the more strict language in 5th edition is to try to make it easier to understand for readers new to the concept of initiative, which I applaud, but a note similar to the one above in a side bar might be required
Additionally the Ready action description could be easily fixed by replacing the word 'round' with 'combat' in the first paragraph, and editing the reminder text about reactions to fit the actual description of a reaction.
However there many be other areas of the rules that use the term "per round" or something similar. Those sections would likely also suffer from this issue as well.
A readied action can occur at any time before the beginning of your next turn, as soon as the trigger condition happens.
It can be later in the same combat round or early in the next combat round. The rules as worded may not seem to say that, but that's what is intended.
The words "turn" and "round" do not have the same meanings in 5e as they did in 3.5e or earlier editions. This can make the 5e rules seem confusing.
I have asked the same questions before. The answer is that they are just poorly worded sentences. They shouldn't use the word 'round' when they don't properly define different usage of the word in the rules.
There 2 kinds of "rounds" in play. The Combat, or Inititative, Round which starts at 30 and decreases to 1. Then there's the Characters Round, which starts on their first turn in combat and continues to their next turn in combat.
The Ready action is based on a character round. Just like Spell Duration is.
E-Tallitnics wrote:
BoldItalic wrote:
this is just thoughts and i dont know intent at all meant by dev's nor do i have a firm opinion on how this reads or how i think it should work, this is just a though:
shouldnt being lower in initiative be a penalty? if you play it where you can hold until your next turn, only the 1st round is a penalty to a low initiative because after that the lowest INT could just ready every turn. it's supposed to "suck" if you roll low.
i am just being devils advocate, but i can see how each is fine. also monsters could also be penalized if they roll low too, so it seems balanced in a way. either way someone thinks it should be, the lowest int is either penalized, or they just ready a ton more to usurp the initiative away from higher rolls, which then makes me wonder why you rolled INT at all... sure thats extreme, but sometimes if you think about something using an extreme is a way to see how silly or similiar the two ponts actually are.
Natbuk also bring this issue here: http://community.wizards.com/comment/51078521
FWIW, Ready works pretty much the same way since Playtest Packet 060713 after it was updated to remove the following sentence;
Ready An Action: Once you have taken the reaction, your place in the initiative order changes so that you act directly ahead of the creature or the event that triggered the readied action.
Plaguescarred wrote:
And here is the tweet:
@chimerasame : Can a low-init character ready an action, then take that action if legit triggered by a high-init character in the next round?
@mikemearls : yes
Thanks MightyZehir. At least its confirmed RAI 
MightyZehir wrote:
It cannot be "1 reaction per turn" otherwise you'd be able to use one on every creature's turn like Sneak Attack for exemple.
I don't see conflicting rules here since everyone normally has 1 turn in a round. The only exception for PC that i know is the rogue feature Thief's Reflex, which lets it take 2 turns in the 1st round of combat. And IIRC, Mike Mearls answered that in this case he'd be able to take 2 reactions, since the start of its next turn occur within the same round.
E-Tallitnics wrote:
Plaguescarred wrote:
E-Tallitnics wrote:
shivafang wrote:
MightyZehir wrote:
shivafang wrote:
shivafang wrote:
Plaguescarred wrote: