When it comes to border, it is quite fascinating to first consider that English as we know it, is totally screwed and bastardized.

Bord-er in its original sense was made of wood. A shield actually. In this sense it is also interesting to consider what is painted on shields? Even today, shields convey jurisdiction.

Later, it is related to the bord of a ship. Hence: star-bord. But also poles driven into the ground to encompass a piece of land showing it is yours.

But also "platje" better known to English speakers as plate. Bret is equally connected to bord, as it means a playboard, like a chessboard.

I dunno what happened to English past the 14th century. But there once was a time when we in North Western Europe could easily comprehend one another, despite the differences in speech.

So, a border is nothing more than a series of poles driven into the ground to signal an allodial claim.

A boarder is equally connected to it, as the boarder actually enters a ship, on board, or on bord, that person enters a different jurisdiction as the shape and size of the ship.

This also shows to total incongruity. Border is a thing, yet a boarder is a person. You can't make this shit up.