On the Abstracted Round Confusion
In 3.x A combat round is six seconds.
In Second edition, A combat round is a minute, made up of 10 six second segments.
This is all we can say with certainty.
For the purposes of my current game, a combat round is a reasonable length of time that varies according to circumstance.
A turn is a 10 minute period related to the movement you can accomplished while cautiously moving and exploring. It is equivalent to your turn in chess or a board game.
For the purposes of play a combat round contains time for the characters to take one move equivalent action and one standard action, and those mean exactly what you think they mean. They may also engage in other minor and free actions without difficulty.
It doesn't matter how long a round is. It's as long as it takes for all members of both sides to take their action.
A die roll is not one sword swing or a full minute of sword play. It is an abstracted attack. (If you are engaged with multiple hostiles, your target is selected randomly.)
Each missile weapon roll to attack is a separate missile shot. Two may be made a round. The explanation which is galactically unimportant is that they are taking time to aim. (Arrow targets are random - anyone in melee with your target has a chance to be hit.)
Psionic combats have two exchanges per round.
When looking at and thinking about the original rules and scale and a hundred other poorly defined things that were defined poorly because everyone knew how they worked, only we don't now; I've discovered that I find I believe that turns were rounds as we think of them, and when melee was 'engaged' those engaged attacked each other up to 10 times before movement or spellcasting was allowed again!
How about them apples? (I'm not going with that, because, well, we're playing a game. And in this game, I get a turn, and then the players get a turn.)