I like to think of it as an abstract slice of camera time to take a turn. In 4e, I've run scenes where a round flexed from 6 seconds in the beginning to 30 seconds toward the middle, and back down to 6 seconds toward the end of the scene. I've also run one scene where rounds were about 1 minute. These were all combat scenes.
It doesn't matter how it's spelled out, 6 seconds, or 10 seconds is fine, with the caveat, DM can adjust as needed for the scene.
It doesn't matter how it's spelled out, 6 seconds, or 10 seconds is fine, with the caveat, DM can adjust as needed for the scene.