Each round represents 6 seconds in the game world. A round presents an opportunity for each character involved in a combat situation to take an action.
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.