Here’s another pair of words where the mix-up seems to only go one way. I constantly see people write ‘boarder’ when they mean ‘border,’ but never the other way around. I wonder why that is?
Border: the edge or boundary that defines an area, that separates one country, state or other geo-political territory from another, or a decorative element designed to enclose an area.
Boarder: a person who is served meals as part of an arrangement, such as a lodger with meals included; or a member of a boarding party; or someone who rides a skateboard or surfboard.
Border comes from around 1350, from the Middle English bordure, which comes from the Old French bord meaning a ship’s side, edge.
Boarder is much older, from before 900; it’s also Middle English, from bord, meaning board, table, or shield.
If you talk about a decorative boarder, you are referring to renting a room to somebody who is pretty.