We should probably discuss this on some article's talk page, and we did. Then admins deleted that article - at my suggestion. So I feel I should revive the discussion.
The producers called the season six off-island action "flash sideways". So we started calling the world the "flash sideways time-line" or the "flash sideways world". But:
- They aren't flashes. We flash to them, but it's no more a world of flashes that Iraq is a flashback world.
- They aren't sideways. We view them alongside the main narrative, but that's the same with secondary stories from throughout the series.
- There is no time in the afterlife. (This one's a joke, sort of. But lists are cooler with four items.)
- It's not a separate timeline.
What do we call the article that describes the afterlife? We can discuss that on its talk page. I want here to say that we should headings on characters pages and elsewhere that cover what happens in the afterlife... something besides "flash sideways". Something descriptive, like "afterlife" (not Purgatory) or "after life" or "post death" - that last one requires that we rename what we now call "post-death".
We don't need to title sections using names the producers have given us. We never have before. Characters don't have giant sections called "Flashback timeline" or "Flashbacks". We call these sections "Before the crash" or "Before the island". We don't have a big heading called "flash forwards". Some pages may list flash forwards as a subheading, but most don't even do that. Instead, we use the heading "After the island". Similarly, even if we keep calling the narrative technique "flash sideways," we needn't title character history headings the same way.