What is another word for border?

There are many words you can use depending on the context. Here are some options:

Formal:

* Boundary

* Frontier

* Perimeter

* Margin

* Verge

* Edge

* Rim

* Circumference

* Outskirts

Informal:

* Line

* Edge

* Limit

* Fringe

* Outside

Specific:

* National border: Frontier, boundary line

* Geographical border: Divide, watershed

* Physical border: Frame, edge

* Digital border: Margin, edge

Figurative:

* Threshold

* Limit

* Point of no return

To give you the best alternative, tell me:

* What is the context? (e.g., a geographical border, a physical border, a figurative border)

* What is the tone you want to convey? (e.g., formal, informal, specific, figurative)