Doorways are meeting places

Oxford University Press states a threshold, “symbolically marks the boundary between a household and the outer world, and hence between belonging and not-belonging, between safety and danger.”

Merriam-Webster states, “A threshold is a transitional interval, beyond which a new action is likely to occur.”

Between these two definitions – one tinged in negativism, the other in optimism – I discern that “threshold” is, at once, an end point and a place where something begins. Whether what was left behind is better than what lies in wait depends, I suppose, on the reason one crosses a threshold, any threshold. Endings and beginnings join in the same place; of course, you can’t see this unless you’re standing in the same plane as the threshold.

That's a view not easily achieved.